Re: Fresh 350 in a 74 Chevelle

by bigredlaguna Sun Mar 19, 2017 1:40 pm

I am working on getting the transmission swapped out. I do have a friend that rebuilds transmissions, and he had a unit ready to be built, so I swapped him one that was under my bench. Got the correct gears for the speedo also.

Fresh 350 in a 74 Chevelle - Page 2 74_tra10

Fresh 350 in a 74 Chevelle - Page 2 74_tra10

by bigredlaguna Mon Mar 20, 2017 9:39 am

Did a quick teardown of the old transmission. The snap ring on the shaft that holds the center support together came off or was broken. My builder said that happens from too much end play. That ring must be the metal flake I saw in the oil because it was completely missing.

by bracketchev1221 Mon Mar 20, 2017 10:30 am

Is the converter stock as well? A little extra stall in the converter will help it accelerate as well. I would look for about 2200 stall to not affect highway cruising.

by fasrnur Mon Mar 20, 2017 8:32 pm

I used a converter out of Super Turbine 300 for many years behind my mild 350 with great success. It stalled right around 1900-2100.

by bigredlaguna Mon Mar 20, 2017 8:48 pm

I would say that the convertor is a stock or near stock stall. The transmission it came out of was in another car of mine that had a 383 w/280 magnum cam. I remember it not taching up like the engine needed so it was a bit lazy from a stop. I'm not really concerned with having a higher stall at this point because this engine has some crazy off idle torque. For me it will make a nice control to see what just the rear axle changes will do for performance.

by bigredlaguna Thu Mar 23, 2017 10:26 pm

This is getting ridiculous........ turns out the posi is a piece of whoa nelly. The driveshaft spins, but the tires do not rotate. Guess I'll be looking for a different carrier. Anyone have a good unit that you don't need/want? PM me please if you would be willing to make a deal.

by bigredlaguna Sat Mar 25, 2017 6:49 pm

This happened after only rolling backwards about 2 car lengths while turning. I bought this years ago before I learned about the suspect nature of the Auburn unit.

Fresh 350 in a 74 Chevelle - Page 2 Junkau10

Fresh 350 in a 74 Chevelle - Page 2 Junkau10

by bigredlaguna Sat Mar 25, 2017 6:51 pm

Just purchased a NEW Eaton carrier.

by bigredlaguna Sat Mar 25, 2017 7:32 pm

I think the cross shaft was missing. Can't find it in the debris.

by bigredlaguna Sat Mar 25, 2017 7:39 pm

This is all there was in the housing. The turn must have made one of the spider gears crawl out.

Fresh 350 in a 74 Chevelle - Page 2 Debris10

by bracketchev1221 Sat Mar 25, 2017 11:04 pm

The cross shaft would have been installed after the axles were in on a c-clip setup. It's very common for them to not be in a removed differential.

by bigredlaguna Sat Mar 25, 2017 11:18 pm

This was probably a good unit, I just feel stupid for not noticing this. The gears seem to be ok, so I am going to just transfer the ring gear to the new carrier.

by bigredlaguna Thu Apr 06, 2017 1:42 am

Finally got to the point where I could test drive it. Still have a leak from the cooler lines that is aggravating me. They don't leak at idle or free rev but they leak badly when tire speed is 30 mph or more.

Also, the posi didn't fall apart on me, but it sure sounded like it wanted to. Are Eaton units noisy until the clutch packs have gear oil in them? Due to the transmission leak, I only got a few blocks travel time on it. Sounds like bare metal rubbing, and it had some spool effect, but it did seem to get a little better in the short distance I drove/turned it.

by bracketchev1221 Thu Apr 06, 2017 6:20 am

bigredlaguna wrote:Finally got to the point where I could test drive it. Still have a leak from the cooler lines that is aggravating me. They don't leak at idle or free rev but they leak badly when tire speed is 30 mph or more.

Also, the posi didn't fall apart on me, but it sure sounded like it wanted to. Are Eaton units noisy until the clutch packs have gear oil in them? Due to the transmission leak, I only got a few blocks travel time on it. Sounds like bare metal rubbing, and it had some spool effect, but it did seem to get a little better in the short distance I drove/turned it.

Did you do the break in where you drive it in tight circles in one direction and then the other?

by ant7377 Thu Apr 06, 2017 6:23 am

When I had the Eaton unit installed I went in a big parking lot and did a bunch of figure 8s . Just nice and slow about 10 times and its nice and quiet.

by bigredlaguna Thu Apr 06, 2017 9:22 am

I was on my way to the parking lot to do the figure 8 thing when the car started doing its best Cheech & Chong impression.

by bigredlaguna Sat Apr 08, 2017 5:43 pm

Well, found the leak that I thought was the cooler lines. It wasn't.

by pila Sat Apr 08, 2017 6:11 pm

I had problems with that O-ring on the tail shaft housing , like seeping etc. You may have a really bad O ring in there, like pinched or a bad nick in it etc..

by bigredlaguna Sat Apr 08, 2017 10:27 pm

It had three cuts in it. It looked like part of it got rolled over the sharp edge by the cover on install. Got it changed out and everything is working good. The carrier broke in just fine, it is now nice and quiet.

The seat of the pants feel is a lot nicer, and the 1-2 shift has a nice chirp to it--- at least with these tires. I chose the speedo gears so it would be accurate with a 295-50 tire. These tires are about an inch shorter.

by bigredlaguna Mon Apr 10, 2017 9:31 am

My daughter is really happy with the car as it is right now. She was gone for a college class over the weekend, so we were teasing her with sound clips of the car. Still have some tweaking to do, like adjusting the shift points, but that will wait until after my she gets the right size tires on it.

On that note, how do you know if the carb is too small? It seems like this engine just struggles past 4K rpm. I was thinking of running a vacuum gauge to the inside of the car and see if it rises at higher rpm.

by pila Mon Apr 10, 2017 11:45 am

Great to hear that you have it all sorted out !! Very Happy

by bracketchev1221 Mon Apr 10, 2017 7:34 pm

For a 350 it's pretty hard to run out of carburetor that early. If it's vacuum secondary you can play with the secondary spring tension for earlier opening. Otherwise I would start looking at fuel delivery or valve springs.

by bigredlaguna Mon Apr 10, 2017 8:14 pm

The carb is an Edelbrock 600 cfm. Non-adjustable secondary air valve. It is just that on one of the test drives I was on was on the highway where the speed limit transitioned from 55 to 70 mph and I just couldn't close distance on anybody in front of me. Rpm was definitely below 5k if not below 4.5k.

I got some open time after this week, so I plan to get this solved then be done with this car for a while.

by bigredlaguna Tue Apr 11, 2017 10:24 pm

My daughter got some new tires on the back. 295/50r15 on the 8 inch rims.

Fresh 350 in a 74 Chevelle - Page 2 Side_110

Fresh 350 in a 74 Chevelle - Page 2 Left_t10

Now I just gotta replace the power steering pump that decided to crap out today. At least it is still under warranty. I was going to warranty it anyway because it just never sounded right- lots of clicking that didn't sound good.

by bigredlaguna Tue Apr 18, 2017 5:54 pm

Got the new pulley this morning and the pump replaced, and finally got to do a road test with the new tires on it. I had also rigged up a fuel pressure gauge where I could see it while driving. Under load, (as in full throttle up to 75-80) the pressure got down to about 2.5/3 lbs. then went up immediately upon a shift change(4000 rpm) or closing the throttle. So I think the fuel supply is good to go. Tomorrow will be a vacuum gauge test.

The new tires are exactly 26 inches tall compared to the old tires being 24.5 inches. It is hard now to break the tires loose from a dead stop(with a 3/4-7/8 full tank). I do have some tuning to do on the accelerator pump because it does have a stumble to it when mashing the throttle from idle.

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