Manual trans guys -- tips for launching?

[PhilaTruck]

Originally Posted by Jim_PA

Thorley Tri-Y headers, full 2.5" mandrel bent Magnaflow header back kit with X-pipe.

Just saw a post linking a CHP article by Lemon Headers. Page 3 talks about Tri-Ys and how finicky they can be. I dunno if he's just blowing smoke, but you're times may be telling.

[Jim_PA]

That is the only factor I can think of as to why I lost ~4 MPH in the 1/4 since I switched to the Tri-Y's

[Wild83C10]

Well the trap speed and ET are pretty close so I don't think you will get much more out of it as it sits.

What are you ****fing at? Have you tried shifting it later and keep it in 3rd?
What are the flow numbers on the heads?
A cam change may help depending on the heads.
I wouldn't change the carb, the Q-jets are more forgiving then the Holley.

[Jim_PA]

Originally Posted by Wild83C10

Well the trap speed and ET are pretty close so I don't think you will get much more out of it as it sits.

What are you ****fing at? Have you tried shifting it later and keep it in 3rd?
What are the flow numbers on the heads?
A cam change may help depending on the heads.
I wouldn't change the carb, the Q-jets are more forgiving then the Holley.

I'm shifting right around 58-5900.

I did keep it in 3rd once, didn't seem to make a difference.

These flow numbers are from the Edelbrock website: (oh, and max valve lift is .575)

lift - Int./Exh.
.100 67/58
.200 130/108
.300 183/144
.400 226/169
.500 229/175
.600 232/182

[383Ram]

But getting back on topic, even though the current combo probaably won't do more than it is now, getting the 60' ft times down is what were after. That is going to be in the launch technique. My personal experience says launch at a higher rpm. You said at 3500 it bucked---when mine did that (in my car i had), i launched higher--4500-5000rpm was the norm for me. Anything less than that and it was a dog off the line. But as i mentioned, it might and probably will break parts. Its a fine line to walk. I can only suggest at this point to launch higher and slip the clutch every so slightly when launching. I dont think the cam change will help you any more, other than killing some bottom end---and all the more reason to launch higher in my opinion.

[Jim_PA]

What do you think about solid cams? I drive it about 3,000 miles a year (maybe...)

Already have the Pro-Magnum rocker arms, and the 270H is already kinda noisy...

Just throwing it out there

[cableguy0]

you can go with a bigger cam without going solid lifter. the lunati voodoo line are nice aggressive cams and still hydraulic.

[Jim_PA]

But what I think I'm seeing in more aggressive hydraulic cams is that you give it up on the low end.

The advertised RPM on solid cams seems to be a much wider band.

This is just from browsing hydraulic and mechanical cams, so maybe it's not the case.

Also, on simliar grinds, won't the solid lifter cam make a significant amount more power?

[383Ram]

When the cams get bigger, the power band moves up in the rpms. Depending on the entire combo, this may or may not work---in your case, i dont think it will work well. You need some leverage to get that boat moving. Gears would be a good place to do this---4.10 or bigger---but then you use drivability. If you go bigger gears, then you can run a bigger cam because you can make more power and get the rpm's to be where they need to to work with the cam. This is the short explination,, but if you look in cam catalogs, they have some specifics that go with them. Comp cams has a nice little free download program that helps pick cams.

I also nowadays would not even consider a cam unless it was a roller. Being a small block, you can do the conversion real cheap--under $400--or cheaper if your thifty. This is due to the rash of flat tappets getting wiped out due to the change in oil formulas. Why go through all the work only to wipe out a new cam. I know there are zinc additives, and some oils that canm be used safely, but why even chance it. Plus almost anything i have put a roller in or had friends that did, we will never go back. The ramps on the cam can open the valve much quicker and get the mixture into the cylinder faster.

If this is strictly a toy and you can spend some money, i would do the following, gears--4.10, cam--hyd roller, eddy RPM intake, full length headers, pull the heads off and cc the heads and see how far down in the hole the pistons are, and get the cc spec on the headgaskets to get the exact compression ratio. You might be surprised what it really is. then pick the cam last.

[383Ram]

Also, lose some weight off that thing if your any type of serious about going faster. Even if you get 400lbs off that thing you'll be miles ahead.

[Jim_PA]

Originally Posted by 383Ram

If this is strictly a toy and you can spend some money, i would do the following, gears--4.10, cam--hyd roller, eddy RPM intake, full length headers, pull the heads off and cc the heads and see how far down in the hole the pistons are, and get the cc spec on the headgaskets to get the exact compression ratio. You might be surprised what it really is. then pick the cam last.

Gears, not yet, because my ultimate goal is a Tremec TKO-500 (they have a 3.27 1st gear) -- Already have Performer RPM intake. I might try to stay with the Tri-Y's, but I could probably sell them and have the cash from that to get a set of Hookers again.

I don't want to go so far as to pull the heads, but I could because a .015 shim would give me a better quench area than with the .039 GMPP head gaskets.

Deck height .021
GMPP .039 head gaskets
quench: .06
static compression: 9.9:1

What are the details on a $400 roller cam swap?

[Jim_PA]

How about the XS274S?

http://www.compcams.com/information/...ess/XTREME.PDF

RPM range 2,000 - 6,400

My 270H is 1,800 - 5,800

[Jim_PA]

Yeah, I'm throwing another one out here... More just so I don't have to bookmark everything

http://www.lunatipower.com/Product.aspx?id=1966&gid=284

[383Ram]

The comp program came up with the comp hyd roller part# 12-413-8. Its a 270/274 hyd rolller with .474 lift 111 lobe center 107 centerline. Thats a nice cam for the combo and weight/gear you have.

In a nutshell, The cheap roller part is you can use factory parts to retrofit your motor---i bought a whole setup on ebay last year for $100. Then just buy the cam of your choice--the most expensive part and pushrods of the correct length---measure per application. If you have a junk yard near you, you may be able to scavange the parts cheaper. You need the lifter tie bars, the spider retainer, and lifters from a FRONT wheel drive car--like a 3.8. The bad part is, to do it right, the motor needs to come out as there is grinding on the block involved. I am assuming of course your block is not setup already for a roller cam.

Just noticed the 12-420-8 is a nice came also, similar, has .500 lift on a 110 lobe sep 106 center---i like the tight centerlines myself---well, at least they always worked in a Mopar, LOL

[Jim_PA]

Thanks for the legwork, Ram -- and I'm not brushing off your suggestions for just trying to get better 60's for better ET's... I'm certainly going to try to do better in the Spring.

I've checked into the "dirt cheap" 3.8 parts roller conversion, and the big downer is tearing it down to do some light block modifications. I've also tried pricing out a retro roller cam from Howards (which seem cheaper than anywhere else...)

I have been reading a lot of good things about the Lunati 401A3LUN solid lifter mech. cam... Only thing I haven't read into is how much of a gain I can expect. Hopefully the lunati tech department can give me a ball-park idea of a swap like this would be worthwhile. Many people (including the designer...) have also stated that this cam is very street friendly (I have manual discs, and a manual trans, so vacuum at idle isn't a huge concern anyway..) and doesn't require much attention as far as re-setting lash goes.

I'm thinking if I can stretch out 3rd gear through the lights, it might be of some benefit, rather than shifting into 4th a couple hundred feet through the lights. This way, I can keep my 3.73's for when I switch to a Tremec when I come up with $2000.00

[CreditGod]

Call the guys at norfleet ask for a guy named johnny tell him your set up they have the specs on any cam on the market including nitro cams hey can usually tell you with in 15 horse power of where you will be plus you can buy one of their cams and save big bucks.

They have a machine called a cam doctor it reads the lobs along with lift and duration and then it makes a copy kinda like a key grinder.

I myself like hydrolic over solid lift because I don't like resetting my lifters but when i can afford it I always like roller over everything because of longevity and no maintenance just my 2cents

[383Ram]

I like solids, but but doing the run on the valves a couple of times a year doesn't sound like fun in a truck. It was fine when i had my car and could just lean over the fender to do it. That to me is the big turn off in a truck--but not a deal breaker. If you are going to stick on a flat tappet though, i think i'd rather go solid over hydralic.

I honestly would have zero problems pulling the motor and buying a gasket set to do the conversion, but i understand completly of not wanting to do that. Trust me i know about the priceiness of roller stuff, there is no cheap way on a big block. I am looking in the $1000 range to do mine, but i may go solid roller which does save a few dollars---we'll see, but mine for sure is definatly getting a roller no matter how long it takes me to get there.

I also did some quick calcs, if your motor specs are what you say they are, yes, you are just shy of 9.9 to 1, which is real healthy--as i am sure you know. Me personally, i dont trust manufactures specs all the time so i always cc stuff to double check. The head gaskets are pretty standard, its probably safe to say the heads are close being aftermarket, but its the deck height i am truly wondering about. Even so, you should definatly be around 9.5 at the least. I am just worried about you over camming the combo is all, or moving the power band away too much down low to get that thing moving.

I do like the lunati solid you posted earlier, it has nice quick ramps in it compared to the comp, i think if you were going to do it, it'd be my choice. Just make sure you are going to run oil with enough zinc in it or get the addative to add in.

[Jim_PA]

I'm tall, and not afraid to keep up with the adjustemnt. Like I said earlier, many have reported with poly locks, only needing to set it once, and then do it maybe once after the cam is broken in...

even if I'm not that lucky, I'm OK with it

Thanks for the tip CreditGod.

[swb85]

Did I read that correctly that you're geared so high that you can cross the traps in 3rd gear??? If that's the case then you've found your problem, not shocking that it's slow off the line with highway gears and 4200+lbs. If you want optimum performance in the 1/4, you need to be finishing at the top of 4th gear.....get yourself some 4.56's out back and you'll cross the stripe at ~5800rpm in 4th instead of 3rd and you'll actually be able to get that sled moving off the line. Putting a bigger cam in that motor isn't going to do a lick of good at the dragstrip with those tall 3.73's.

[Jim_PA]

Yeah, but I'm cruising down the highway now 3500 RPM @ 75 MPH.

Wanting a Tremec for 3.27 first + OD.
currently running a 2.64 first gear.

The 3.27 of the tremec would reduce 1st gear by 25% -- I might want to do 4:11's at that point, but I'll figure that out after it's in.

[383Ram]

Gee, i wouldn't consider 3.73 a tall gear. I thought he said he might maybe try and cross the line in 3rd to see what'll it do. I think myself it'll over rpm at that point unless all of the shifts are held longer--and then maybe it still might over rpm. Just things to try for next year i guess.

Keep us updated on what happens.

[WyoGMC]

I agree gears can can make the difference off the line. Why not go to a shorter tire to get a lower gear ratio?

[Jim_PA]

Originally Posted by WyoGMC

I agree gears can can make the difference off the line. Why not go to a shorter tire to get a lower gear ratio?

Gearing would give me the best gains, but I'm not going to do that until I get a new trans.

I guess I could mount some 23 or 24" slicks on the truck, but I'm not sure I can bear the thought of how goofy it would look. I guess if it worked, the joke would be on everyone else who was laughing at me

[Jim_PA]

Originally Posted by 383Ram

Gee, i wouldn't consider 3.73 a tall gear. I thought he said he might maybe try and cross the line in 3rd to see what'll it do. I think myself it'll over rpm at that point unless all of the shifts are held longer--and then maybe it still might over rpm. Just things to try for next year i guess.

Keep us updated on what happens.

I held it in 3rd gear on the first run. At 5500+ in 3rd gear going 90-some MPH, the revs weren't climbing very fast (remember... it's a 4400 lb shoe box going down the track ). It spooled up in third to about 6000 RPM through the lights.

Part of my knuckle-headed theory is that if I can get a cam that will let me keep about the same low-end power, but have more power up in the 5500-6500 RPM area, maybe I can get it up to 6500 in 3rd gear, which would turn out to be about 102 MPH... supposedly, this is where solid flat tappet cams excel -- keep the low end, and make substantially more power in the upper RPM range.

Comp cams has a pretty neat article where they sculpted a solid lifter flat tappet cam with very similar specs of an off-the-shelf hydraulic flat tappet cam. Now, I realize it's not my engine they are doing the article about, but the results at the bottom of page 28 are pretty impressive in my book: http://www.compcams.com/Community/Ar...?ID=1088792917

Maybe I still won't have enough power to accomplish 64-6500 in 3rd gear through the lights, but it sounds like a fun experiment.

[CreditGod]

Ok I have had enough my dad ten years ago built a driving truck that would do 6.70's in the 1/8 and this is what he tells me

A car or truck is built with a purpose in mind daily driver or go fast.

With that being said you have to look at you combination from front to back

Motor exactly what compression are you running no guessing what is it?

ignition are you running a MSD box.

Intake single plane or dual plane are you using a 3 inch stack plate for low end torque.

heads what size runners? what size valves? open chambered or closed chambered.

What size springs are you using. what pressure are they set for.

do you have a rev kit. what kind of valve guides do you have.

every cam is built to do something different so what is your cam rated at rpm wise.

What type of rods do you have H-beam rods aluminum rods or stock

what type of pistons are you using forged, hyperutechtic, stock

what is their bob weight

what kind of crank do you have cast or steal

What is the weight of you crank.

Is you engine balanced from the machine shop.

what carb are you using and how is it jetted

what spark plugs are you using

do you have full length headers or block huger headers

do you have a lightened drive shaft.

are you using slicks or drag radials.

are you setting your rear tire pressure up before you do a run in other words setting it up to make a launch and make the truck go straight.

also is your cam timing set up normal or 3 degrees advanced or 3 degrees retard timing

If you will take the time to answer all of this I will be able to tell you what you need do do to get better 1/8 mile times or 1/4 mile times

I just want to try to answer your quest with out any BS