Loss of power after RP swap

[curvedglass]

I am new to the board and looking for a little advice. I recently purchased a 63 short wide which I want to take over daily driver duties. I like the 230/3 spd for efficiency however the previous owner swapped in a set of 3.08's. I am getting 19 mpg but I can't make it to the top of the hill without constantly rowing from 2-3 and best speed is about 45mph with the clutch chattering away. It just runs out of gear. I plan to keep this truck for a long time and as I get older clutching is getting to my knee. I am considering a 700r4 swap. My concern is that I will still be stuck with a truck that can't make it up the hills? Will the 700r4 make the truck a better driver, or would a 5 speed be a better solution.

I thought of hopping up the six but then I use more fuel and lose the mpg.

[Tx Firefighter]

Swapping a 700r4 or a 5 speed is going backwards. Your main complaint is that the 3.08 gears won't allow the engine to pull hills without downshifting. Adding an overdrive on top of that with your trans swap will just further aggravate the frequent lugging and shifting issue.

A turbo 350 would be a better trans choice. It would drive just like it does now down the road, but when it needed to downshift the trans would do it rather than you having to manually do it.

I don't know the type of hills you're dealing with, but I strongly suspect your engine needs tuning or something similar. It sounds like you're down on power from where you should be. An unloaded swb truck with a 230 and 3.08 gears ought to motor up most any hill at highway speed without too much difficulty or down shifting needed.

[Clyde65]

What TX Firefighter said!!!!!

That 230 and 3 speed should have enough power to get you up any moderate hill without downshifting.

[davbowen]

you could change out to a taller gear set in the rear and keep the 3speed. but if your going to an auto, then the best would be what TX Firefighter said.

[Tx Firefighter]

Before I started making changes, I'd maximize what you already have.

1) fuel system. Make sure the sock in the tank isn't clogged, fuel pump is strong, any/all fuel filters are clean and the carburetor is clean and well adjusted. Clean air filter.

2) ignition system. Six good plug wires, six good properly gapped spark plugs, strong spark from the coil. Personally I go to HEI on every six I've owned. It makes them start and run remarkably better.

I'd bet you're down on power which is causing your frustration.

[AcampoDave]

And make sure your clutch isn't slipping

[1963c-10]

You can always convert to a hydraulic clutch and give your knee a rest also on the mechanical clutch.

And welcome...always glad to see a new 63 pop up.

[AcampoDave]

Originally Posted by 1963c-10

You can always convert to a hydraulic clutch and give your knee a rest also on the mechanical clutch.

And welcome...always glad to see a new 63 pop up.

True, and I found just changing from a 3 lever style pressure plate set-up to a diaphragm style helped a lot with that too.

[chevy_mike]

What you haven't posted up is what RPM range are you at when you have to downshift while going up the hill. Sweet spot for the inline 6 engines are around 2100 RPM. Below that, they don't have a lot of power and with the 3.08 gears, you're likely falling off the power band.

Also keep in mind, even bone stock new, these engines are only putting about 120 HP to the ground. An old, higher mileage one is likely luck to be at 100 HP. That's not much given the truck weight and brick aerodynamics.

Don't be afraid of spinning it up a little. My '64 Chevy II wagon, at 70mph, is at 3300 RPM's. You might need to downshift into 2nd and leave it there until you crest the top of the hill.

[curvedglass]

thanx for the info guys. I have replaced everything under the hood tune up wise. Plugs, cap, rotor, fuel pump, coil, wires, and a petronix module. the carb definitely needs a rebuild. I have the kit but have been driving too much to want to take it off the road for down time. I have a complete CPP disc brake kit and new springs all around. I will build the carb when it is down for that work.
Some one else told me that a TH350 loves the highway gears and should work nicely
I do not have a tach so I am not sure of my RPM's. It doesn't sound like I am killing it. The hills aren't too bad and my issues are usually from a dead stop. If I have some good speed going I do not lose too much. Maybe drop 10-15 mph.
The clutch is original and in need of replacement so maybe that could be a culprit as mentioned above.

[TJ's Chevy]

Just know that those 230's are 4000 rpm motors. Peak 125 HP at 4000 RPM and about 230 pound feet of torque at 1000-1200. Putting a bigger carb does not mean it will get worse mileage. I'd bolt on a 2 barrel and a nice set of headers and you'll get better mileage that way( and a little more power). I have a 600 cfm edelbrock 4 barrel and headers on my 292 and it gets better mileage simply cause its not starving for fuel. I also have an HEI on it as well. You can check out my build for more info(link below). As said a TH350 auto would help alot...also another good choice would be a richmond non-od 5 speed. Gives you 5 close ratio gears which would help in down shifting..and I will repeat, This isn't an OD trans.

[curvedglass]

Originally Posted by T.J. MCCAULEY

Just know that those 230's are 4000 rpm motors. Peak 125 HP at 4000 RPM and about 230 pound feet of torque at 1000-1200. Putting a bigger carb does not mean it will get worse mileage. I'd bolt on a 2 barrel and a nice set of headers and you'll get better mileage that way( and a little more power). I have a 600 cfm edelbrock 4 barrel and headers on my 292 and it gets better mileage simply cause its not starving for fuel. I also have an HEI on it as well. You can check out my build for more info(link below). As said a TH350 auto would help alot...also another good choice would be a richmond non-od 5 speed. Gives you 5 close ratio gears which would help in down shifting..and I will repeat, This isn't an OD trans.

cool info. you guys are awesome over here. Got the link from the H.A.M.B. I'm lowcad61 over there.

I have been looking at a clifford / holley 390 set up with Langdon cast headers. I would entertain a 2bbl / glasspack just because of cost savings over the 4bbl / header. I want to keep the six even though I can buy a goodwrench 350 for the price of the six mods. Just dig the OG factor.

Who makes a 2bbl adapter for the intake?

I would definitely look into an automatic swap if I am going through the trouble. That is how I ended up with this truck. Cheap parts and easy auto swap. I am looking to get out of my 94 Mustang GT daily driver. Been sitting down that low and rowing the T-5 for 201,000 miles. My left knee is on the way out and Trucks are more ergonomically correct for the body. I drive 75+ a day.

[TJ's Chevy]

Originally Posted by curvedglass

cool info. you guys are awesome over here. Got the link from the H.A.M.B. I'm lowcad61 over there.

I have been looking at a clifford / holley 390 set up with Langdon cast headers. I would entertain a 2bbl / glasspack just because of cost savings over the 4bbl / header. I want to keep the six even though I can buy a goodwrench 350 for the price of the six mods. Just dig the OG factor.

Who makes a 2bbl adapter for the intake?

I would definitely look into an automatic swap if I am going through the trouble. That is how I ended up with this truck. Cheap parts and easy auto swap. I am looking to get out of my 94 Mustang GT daily driver. Been sitting down that low and rowing the T-5 for 201,000 miles. My left knee is on the way out and Trucks are more ergonomically correct for the body. I drive 75+ a day.

Trans adapt makes a 2 barrel adapter. You probably should purchase a turbo muffler instead..it will help make a little better flow and meaner sound. I have an adapter if your interested. Do keep in mind though that a header swap would help make better power and more mileage.

[curvedglass]

cool. I'm holding off until I do the rebuild of my 1bbl. I already have the kit. I want to see how much better (or not) it will run when I am finished. My carb rebuilding experience is limited to the 1bbl up draft on my old Ford 3000 tractor and it ran great from the first crank. What type of carb hooks up to that adapter? Weber? Holley? Stock Rochester?What would the CFM be?

[TJ's Chevy]

Originally Posted by curvedglass

cool. I'm holding off until I do the rebuild of my 1bbl. I already have the kit. I want to see how much better (or not) it will run when I am finished. My carb rebuilding experience is limited to the 1bbl up draft on my old Ford 3000 tractor and it ran great from the first crank. What type of carb hooks up to that adapter? Weber? Holley? Stock Rochester?What would the CFM be?

Those one barrels are super easy to rebuild. Holley 350 or 500 cfm 2 barrel will bolt up to that adapter. I forgot to mention that Tom Langdon makes a 2 barrel weber adapter as well. Langdon Stovebolt. com for prices. I prefer to holley cause they aren't as big a pain as the weber when it comes to tuning. A 350 cfm holley will be fine...I wouldn't do a 500 cfm 2 barrel holley unless you convert to headers.

[LVPhotos]

I would have to say the auto trans would take 30-40% power away from motor. A good cruise speed is around 2000 for most motors. Gear accordingly. I too have knee problems but still like the manual shift. Check clutch for wear and oil saturation.

[AcampoDave]

Could it be that a clutch is like physical therapy for old knees and without it we'd only be more atrophied? When I got my knees repaired the doc wanted me to keep them working . Soooo I drive my truck as much as possible. Do manual brakes count for the right one?

[LVPhotos]

Originally Posted by AcampoDave

Could it be that a clutch is like physical therapy for old knees and without it we'd only be more atrophied? When I got my knees repaired the doc wanted me to keep them working . Soooo I drive my truck as much as possible. Do manual brakes count for the right one?

Manual brakes for the sphincter! Nothing like a little pucker action. I use hand eye coordination holding a drink, manual steer, shift, left foot on clutch right on gas and clutch.