Chevy 350 rebuild opinions

[rdauphinais]

This summer i will be pulling and rebuilding my 86 350 carbureted.

I need to know if this was a good kit:
http://www.summitracing.com/parts/sum-sbckit1-411

maybe not bored over maybe stock haven't decided yet.

What about a cam? Looking for a mild cam (I think)

This is going into a 86' Gmc K3500 used for pulling a trailer and just regular driving. Do i need a different cam if so point me in the right direction.
Trying to do this on the conservative side considering i also have alot of work to do to my daily driver.

I haven't heard anything about edelbrock cams but what about this:
http://www.summitracing.com/parts/sum-sbckit1-411

any opinions welcome.

[slotard]

Why will you be rebuilding it? What problems do you have with it?

Your links are both to the rebuild kit, so I can't say anything about the cam.

I'd consider replacing the timing chain/sprockets too.

Regarding a cam, it all depends on what you want to do with it. There are plenty of cams available for all different types of driving, in a K30 used for towing you probably don't want anything too aggressive.

[bnoon]

Wait until you pull it apart before you order a rebuild kit. You may find damage that requires .020 instead of .010 machining... or vise versa, may require no machine work. You may not need pistons either. Upgrade to a one piece rubber steel core pan gasket to avoid leaks caused by the original type multi piece.

As for cam, given your intended use (and parts source you linked) I'd choose a Summit brand cam, either the 1101, 1102, or maybe even the 1103.

[rdauphinais]

Thanks for the replies, i may have ceased it, because a gasket blew without me knowing it, i haven't even looked at which one yet, but I was driving it around and the oil pressure was dropping so I was driving it back and all of a sudden it started bogging down and then I let off the gas and it stopped immediately. Like pop the clutch in 3rd gear stop! So I am mad at myself because I know I should have shut it off but I didn't.

Thanks for the replies I will go back and get the link for the cam I was looking at. And look up those summit cams as well. And yes I completely agree on waiting to order it until after I open it up. Leaned my lesson there
Will touch back later.

[slotard]

Looking at the 1101, 1102, and 1103 I see some strange claims.

1101 has the least lift (398/421) and duration (194/204)
1102 has a little more (421/444 lift, 204/214 duration)
1103 has even more (444/466 lift, 214/224 duration)

However, the 1101 claims to rev to higher rpm (4500) than the 1102 (4000).

As they get bigger, the rpm they come on at increases (idle, 1500, 1600) which makes sense.

All 3 have 112 LSA.

I have a Comp Cams 252H (CL12-205-2), 425 lift, 206 duration. It's a good cam for a work truck. The 1102 looks to have similar characteristics to what I have, but with more lift/duration on exhaust. It should work pretty well for a tow rig, and I'd expect it to work well off idle even though they say 1500 and up.

While you have it apart, I'd suggest putting in some basic roller rockers. http://www.summitracing.com/parts/sum-141506 work well for a truck motor, and are cheap.

[Tylerz181500]

i run the 1102 in my tbi and love it, ima go with the 1103 if i go with a summit cam next time. as stated wait to buy your kit as your machine work tells you if you need pistons or not and whatever heads your using etc. if you think its seized and such and have the bank account id start looking into one of northerns stroker kits personally, i love my 383, wouldnt have changed it for a 350 for anything. Comp cams also has a nice selection of RV/torquier/truck cams so to speak id also recommend looking into those.

[rdauphinais]

this is the edelbrock cam i was looking at don't know anything about them:
http://www.summitracing.com/parts/edl-2102

Looking at those summit cams, why not a 1106 or 1107? I'm asking because i don't know. Is it too steep, what are the consequences.

Looking at those stroker kits, and it is so tempting, but i can't find one for my year. 86'
Also, i am (supposed to) try and keep this as low cost as possible.

But i may just wait longer and save up and buy one

[MikeB]

Originally Posted by rdauphinais

Looking at those summit cams, why not a 1106 or 1107? I'm asking because i don't know. Is it too steep, what are the consequences.

Anything bigger than the 1102 in an otherwise stock truck will hurt low-to mid RPM torque and reduce gas mileage -- exactly what you DON'T want when pulling a trailer. In fact, the 1102 is probably too big.

Big cams need higher compression, good heads, and lower axle ratios to work well.

[bnoon]

Originally Posted by rdauphinais

this is the edelbrock cam i was looking at don't know anything about them:
http://www.summitracing.com/parts/edl-2102

Looking at those summit cams, why not a 1106 or 1107? I'm asking because i don't know. Is it too steep, what are the consequences.

Looking at those stroker kits, and it is so tempting, but i can't find one for my year. 86'
Also, i am (supposed to) try and keep this as low cost as possible.

But i may just wait longer and save up and buy one

The 1107 is what I have in my built 350. I run it with flat top 10.5:1 compression, a 3200 stall, a TH400 transmission and 3.73 gears. The ONLY thing I can tow short distances is a single motorcycle or single snowmobile trailer and it's an extreme compromise to tow even that. Most of the time the only thing this truck hauls is butt! Power brakes??? Not without a vacuum canister you ain't!!!

The reason you can't find a kit for '86 is because it's a transition year. You have a one piece rear main seal, but still have flat tappet lifters. This can make certain parts, like gaskets, one year specific to the '86. You can put a kit together yourself talking to just about any one of the companies that offer the kit. If it were me, I'd get it apart and if the crank needs work (most likely a spun bearing or two), then I'd do the stroker. Machine work to the stock crank will cost more than a new Scat stroker crank. With the stroker, you can go with a larger choice cam (like the 1103) as the extra cubes make the cam work much easier.

[68post]

Originally Posted by bnoon

The reason you can't find a kit for '86 is because it's a transition year. You have a one piece rear main seal, but still have flat tappet lifters. This can make certain parts, like gaskets, one year specific to the '86. You can put a kit together yourself talking to just about any one of the companies that offer the kit. If it were me, I'd get it apart and if the crank needs work (most likely a spun bearing or two), then I'd do the stroker. Machine work to the stock crank will cost more than a new Scat stroker crank. With the stroker, you can go with a larger choice cam (like the 1103) as the extra cubes make the cam work much easier.

I agree.

A K3500 is alot of truck to haul empty, a 383 would be a wise choice. A small cam and compression btw 8.5 or 9:1 would be a good idea regardless if you have a 355 or 383.
You can hedge on this a little if you want to run premium all the time and/or have heads with great combustion chambers along good swirl and tumble.

[rdauphinais]

I'm a little confused, i understand about the cams now, but on summit for the kit, it says:

Make:CHEVROLET
Beginning Year:1968
Ending Year:1986
Engine Type:V8
Engine Size:5.7L/350
Liter:5.7
CID:350
Engine Family:Chevy small block Gen I

Does that include my 86' ? And what generation do i have? So i have a one piece rear main seal? And the kit comes with a two piece?

Sorry for all the questions.

[Tylerz181500]

i think the 1102 would be a good choice for his application, even though mines in a yukon it did improve my overall torque down low, tbis also help with that.

as for stroker kits ive built my 383 without a kit for 2600 including all the machining and such but i did alot of shopping around before hand.

[rich weyand]

Get a Comp Cams 12-300-4, 12-235-2, or 12-230-2.

This forum won't let me post a pointer to another forum, so Ima gonna copy and paste a couple paragraphs or ten.

================

A word on cams for you.

12-230-2 will work fine. With dual-plane and long-tube headers, 290hp/420lbft. Lift is .432/.444. RPM range is 600-4600.

12-235-2 will wind a bit tighter. With dual-plane and long-tube headers, 290hp/415lbft. Lift is .421/.451. RPM range is 1000-5200.

12-300-4 is what I am running. With dual-plane and long-tube headers, 275hp/420lbft. Lift is .390/.390. RPM range is 600-4600.

So all of these are in the same ball park. 12-230-2 has the same hp and torque as the 12-235-2, but will run out of pull at 4600 rpm. 12-235-2 will match that, and pull to 5200, which is a better fit with stock shift points. 12-300-4 gives up some hp on top, matches the torque in the bottom, but keeps the stock .390/.390 lift, which is easier on the valve train (and cam lobes). That's why I picked the 12-300-4, for engine lifetime sake, since they are so similar in performance.

All three cams will work with stock lifters and springs. Note: NEW stock lifters and springs.

For the 12-230-2 and 12-300-4, you should replace one weight in the TH350 governor with the next bigger weight to bring the stock shift points down 500 RPM. If it's a stick (sorry, I don't remember and it's a lot of posts back!), then you will time the shifts yourself, so no worries.

The cam that's in there is an old cam design. In an ideal world, valves would be open or shut, with no in-between. That would maximize flow while giving you an earlier intake closing for more dynamic compression and a later exhaust opening for longer pressure on the exhaust stroke. Unfortunately, we can't do that -- cams are ramped. You can tell how long the ramps are by subtracting the .050 duration from the advertised duration.

The cam that's in there has ramps in the mid- 70-degree range. All three Comp Cams have modern computer-aided designs with ramps in the mid- 40-degree range. That's 30 degrees less dead space in both the intake and exhaust cycles. The difference that makes in the ability to tune the other cam parameters cannot be overstated.

I think you will be very happy with whichever of those three cams you pick. Not a bad choice among them, really.

=====================

Subtract the .050 duration from the advertised duration for that Summit cam. It has 74 degrees of ramps, so it's an old grind. Not necessarily a "bad" cam, but just much less capable than a modern design.

A note about lope. Everybody thinks they want it, but what it means is that the engine doesn't want to run at 700 rpm. So how much torque do you think you're going to get at 1000, or 1500? An engine that's going to generate torque at low rpm is going to LIKE running at low rpm, so it will idle really smooth.

The way they get launches at the drag strips out of engines with a lot of lope is to run high-rpm lockup torque converters so they can wind the engine up to where the hp is. High-rpm torque converters are great for the drags, but a PITA to drive around on the street, and they're hard on transmissions.

[68post]

Originally Posted by rich weyand

Get a Comp Cams 12-300-4, 12-235-2, or 12-230-2.

This forum won't let me post a pointer to another forum, so Ima gonna copy and paste a couple paragraphs or ten.

================

A word on cams for you.

12-230-2 will work fine. With dual-plane and long-tube headers, 290hp/420lbft. Lift is .432/.444. RPM range is 600-4600.

12-235-2 will wind a bit tighter. With dual-plane and long-tube headers, 290hp/415lbft. Lift is .421/.451. RPM range is 1000-5200.

12-300-4 is what I am running. With dual-plane and long-tube headers, 275hp/420lbft. Lift is .390/.390. RPM range is 600-4600.

So all of these are in the same ball park. 12-230-2 has the same hp and torque as the 12-235-2, but will run out of pull at 4600 rpm. 12-235-2 will match that, and pull to 5200, which is a better fit with stock shift points. 12-300-4 gives up some hp on top, matches the torque in the bottom, but keeps the stock .390/.390 lift, which is easier on the valve train (and cam lobes). That's why I picked the 12-300-4, for engine lifetime sake, since they are so similar in performance.

All three cams will work with stock lifters and springs. Note: NEW stock lifters and springs.

For the 12-230-2 and 12-300-4, you should replace one weight in the TH350 governor with the next bigger weight to bring the stock shift points down 500 RPM. If it's a stick (sorry, I don't remember and it's a lot of posts back!), then you will time the shifts yourself, so no worries.

The cam that's in there is an old cam design. In an ideal world, valves would be open or shut, with no in-between. That would maximize flow while giving you an earlier intake closing for more dynamic compression and a later exhaust opening for longer pressure on the exhaust stroke. Unfortunately, we can't do that -- cams are ramped. You can tell how long the ramps are by subtracting the .050 duration from the advertised duration.

The cam that's in there has ramps in the mid- 70-degree range. All three Comp Cams have modern computer-aided designs with ramps in the mid- 40-degree range. That's 30 degrees less dead space in both the intake and exhaust cycles. The difference that makes in the ability to tune the other cam parameters cannot be overstated.

I think you will be very happy with whichever of those three cams you pick. Not a bad choice among them, really.

=====================

Subtract the .050 duration from the advertised duration for that Summit cam. It has 74 degrees of ramps, so it's an old grind. Not necessarily a "bad" cam, but just much less capable than a modern design.

A note about lope. Everybody thinks they want it, but what it means is that the engine doesn't want to run at 700 rpm. So how much torque do you think you're going to get at 1000, or 1500? An engine that's going to generate torque at low rpm is going to LIKE running at low rpm, so it will idle really smooth.

The way they get launches at the drag strips out of engines with a lot of lope is to run high-rpm lockup torque converters so they can wind the engine up to where the hp is. High-rpm torque converters are great for the drags, but a PITA to drive around on the street, and they're hard on transmissions.

Can I say that "I agree" again ??

[slotard]

rich, I don't expect to replace my cam but I have a 12-205-2. What would you expect out of it? It has a 46 degree ramp, so about what you said most modern cams have.

[rich weyand]

Originally Posted by slotard

rich, I don't expect to replace my cam but I have a 12-205-2. What would you expect out of it? It has a 46 degree ramp, so about what you said most modern cams have.

Assuming a nicely tuned 4bb carb, dual-plane manifold, long-tube headers:

12-205-2: 279hp @ 4000, 413 lbft @ 2500, .425/.425 lift, 800-4800 rpm.

Yeah, another modern grind. A little more lift than the 12-300-4, a little higher operating range, but not as much of either as the 12-235-2. It's about halfway in between. The torque and hp curves are very close to the 12-300-4, but the 12-205-2 will wind just a bit tighter before it runs out of steam.

If it seems like the 2-3 shift at WOT is a little late (you're wound out before it shifts), you might want to go one size larger on one weight on the tranny governor (assuming an automatic) to move the shift points down a tad.

Comp Camquest lists it as a "Great Fit" for "Increased Economy, Torque, Mild Performance Gain".

All in all, another nice cam choice for a squarebody.

[rdauphinais]

so after a little looking on summit, i would need this rear main seal:
http://www.summitracing.com/parts/fel-2919/all

and if the housing is bad i would need this:
http://www.summitracing.com/parts/sum-150120/overview/

Someone correct me if im wrong

[MikeB]

An earlier model flat tappet cam will fit into any Gen I 350 block, even an 86-up one-piece main seal, roller cam block. However, not all one-piece main seal blocks had roller cam, or were drilled for them.

Look at the casting number on the back of the block to see if you have a one-piece or two-piece main seal. It's on the top ledge of the bock just behind the drivers side cylinder head. On a newer one-piece block it's behind the pass side head.

Many, if not all, of the newer one-piece seal blocks had "5.7LG" cast into the drivers side, and "880" cast on each side of the block under the heads between the freeze plugs. However, there are some one-piece seal block castings (at least 1) other than the 880.

No flak on the overspray, please.

[68post]

Originally Posted by rdauphinais

so after a little looking on summit, i would need this rear main seal:
http://www.summitracing.com/parts/fel-2919/all

and if the housing is bad i would need this:
http://www.summitracing.com/parts/sum-150120/overview/

Someone correct me if im wrong

Those are both to fit a "one piece seal" block, the first is the replacement seal and the other is a replacement seal housing (I'm nor sure why that you think your's may be damaged ).

[Tylerz181500]

Im gonna derail this thread for a second. I love you guys, on every site of been on theres someone arguing with someone else but yall agree with one another and its true factual info, i used to be the give to give recomendations most places even though im not as intellectually inclined about cams as you guys are but its just nice, finally a place where people know what they are talking about..........Proceed.

[MikeB]

Originally Posted by Tylerz181500

Im gonna derail this thread for a second. I love you guys, on every site of been on theres someone arguing with someone else but yall agree with one another and its true factual info, i used to be the give to give recomendations most places even though im not as intellectually inclined about cams as you guys are but its just nice, finally a place where people know what they are talking about..........Proceed.

I hadn't thought about it, but you're right. I haven't posted much here in the past 10-12 years, (having been derailed by a 55 Chevy sedan project) but jumped back in when I got my 82 C10 last year.

Differing opinions here are just that -- not cause for flaming.

[rdauphinais]

thanks everyone for the comments, and yes it's amazing how much everyone helps i was actually expecting an argument about which kit to buy or which cam is better, but that hasn't happen. (Yet)

So not too push the subject, but looking at the stats on all the cams, the edelbrock i was looking at has very close #'s to the comp cam but looking online, everyone seems to like the comp cams and most like the summit, but i only found a few people who like edelbrock cams. So i think i will be getting the comp 12-235-2 but it is hard to say right now, i might change my mind and go with the 12-230-2.

and again thanks for all the help everyone.

[68post]

The Edelbrock cams and Summit cams can be directly compared as "slow ramp" designs,( and may even be ground by the same house), neither would be my first or second choices. Newer Comp cams and newer Lunati cams can also be compared , with Lunati being held in a little higher regard by most.

When throttle response and torque trump horsepower you may consider some single pattern grinds.
There is alot to choose from , usually too much, and most of the tech lines are somewhat off-base. It takes luck, or a tip, to get the right person on the line.

[MikeB]

Two nice things about the old school cams:

1. Slow ramps are easy on the valve train, and can get by with less spring pressure. This means they are much less likely to have problems at break-in.

2. Slow ramps typically make less valve train noise than cams with aggressive ramps. The CompCams XE series is well known for closing the valves a bit quick, resulting in some "clicking" sounds. No such issues with Lunati's Voodoo series, from what I have read on the performance forums out there.

BTW, CompCams still sells their 25-30 year old High Energy line of cams that have relatively slow ramps.

And I probably said this earlier in this thread, but for towing applications you need all the low-mid RPM torque you can get (not horsepower and more revs) and you're not gonna do that with even a hint of a performance cam.

Another quick note: The best pickup truck cam I ever had (for a truck that actually hauled and towed stuff) was recommended to me by Crane Cams back in 1995. It's their #114112. Its specs are 194/204 duration @ .050" tappet rise, .401"/.423" valve lift, and 104 LSA.

In a 350 Goodwrench engine with approx 7.8:1 actual compression, 600 cfm 4 bbl, and dual exhausts, that cam made massive torque from off-idle to 3500 RPM. The 104 LSA got the intake valve closed quickly on the compression stroke, creating lots of cylinder pressure. Vacuum remained stock at around 20". The truck would easily run at 70-75 mph up a 9,000 ft pass pulling a loaded 5x8 U-Haul trailer. Just incredible.

By the way, it replaced a 204/214 Performer cam that I had been running (virtually identical to Summit K1102). There was a night and day difference below 3000 RPM. It pretty much ran out of steam at 4000 RPM, but in hauling and towing applications, who cares?

[rich weyand]

Originally Posted by MikeB

Two nice things about the old school cams:

1. Slow ramps are easy on the valve train, and can get by with less spring pressure. This means they are much less likely to have problems at break-in.

2. Slow ramps typically make less valve train noise than cams with aggressive ramps. The CompCams XE series is well known for closing the valves a bit quick, resulting in some "clicking" sounds. No such issues with Lunati's Voodoo series, from what I have read on the performance forums out there.

BTW, CompCams still sells their 25-30 year old High Energy line of cams that have relatively slow ramps.

And I probably said this earlier in this thread, but for towing applications you need all the low-mid RPM torque you can get (not horsepower and more revs) and you're not gonna do that with even a hint of a performance cam.

Another quick note: The best pickup truck cam I ever had (for a truck that actually hauled and towed stuff) was recommended to me by Crane Cams back in 1995. It's their #114112. Its specs are 194/204 duration @ .050" tappet rise, .401"/.423" valve lift, and 104 LSA.

In a 350 Goodwrench engine with approx 7.8:1 actual compression, 600 cfm 4 bbl, and dual exhausts, that cam made massive torque from off-idle to 3500 RPM. The 104 LSA got the intake valve closed quickly on the compression stroke, creating lots of cylinder pressure. Vacuum remained stock at around 20". The truck would easily run at 70-75 mph up a 9,000 ft pass pulling a loaded 5x8 U-Haul trailer. Just incredible.

By the way, it replaced a 204/214 Performer cam that I had been running (virtually identical to Summit K1102). There was a night and day difference below 3000 RPM. It pretty much ran out of steam at 4000 RPM, but in hauling and towing applications, who cares?

Agreed on everything you said except the implication (which I may be reading in to what you said) that fast ramps are somehow a performance cam, so not good for towing. Performance cams are high lift, high overlap, etc, etc., and are indeed unsuitable for towing. A performance cam may or may not include fast ramps, but fast ramps are independent of whether or not it is a performance cam or a towing cam, or a general-purpose cam, or whatever.

The reason you can get away with fast ramps now is that computers can calculate the cam lobe-lifter pressure at any point in the cycle, at any rpm, for any cam lobe design, and so it is a lot easier to get fast ramps without going "over the edge" and causing the issues you mention.

The 12-300-4 generates 420+ lbft of torque at 2500 RPM, and has 300+ lbft from 1000 rpm all the way to 4600 rpm, with a stock lift and fast ramps. That is my recommendation for anyone doing towing or plow work. I've had it in my truck for three years now and love it. No issues with it at all.

The 12-230-2 has the same bottom end torque as the 12-300-4 with more horsepower up top, but it does this with a 10%+ higher lift. I stayed away from it for the reasons you cited. Fast ramps is enough "extra" without 44-degree ramps pushing a .430-.440 lift.