Thanks Guys, You Solved My 348 Problem!!

[Drive em]

I have been a lurker here for several years. I was building a 348 powered '58 Chevy Apache pickup for my dad, and I came here for information on these engines as I had never built one before. (I am a Ford Guy) The engine is a pretty straight forward .030 over '59 348 with a 340 horse 409 hydraulic cam from Showcars. It has a factory 3 x 2 intake with three Autolite two barrel carbs. (That's the Ford guy in me coming out)

Anyway, I got the truck running two years ago and I have been fighting lifter noise since then. The lifter noise just happened to be overshadowed by a 700r4 that would not work right. The truck spent soooo much time on the lift that I kinda forgot about the lifter noise. The truck would run pretty good, it was just noisy. I tried several things to remedy the problem, but nothing worked.

WELL I got the tranny problem ironed out a few weeks ago, and I took the truck for a drive only to realize that there was something severely wrong with the engine. I spent several hours reading tech posts here in the archives, and I soon realized that the problem was most likely that the rear cam bearing was installed in-correctly. Out came the tranny, out came the rear cam plug, and voila, the bearing was in wrong. I pulled the intake manifold and used a small drill to turn the oil pump with a gutted fully grooved distributor housing on place and I realized that none of the lifters were getting oil at all!!! I made a mandrel on my lathe and using a slide hammer, I pulled the rear cam bearing back 3/16".

I cannot believe the difference in how the engine runs now. Before it kinda sounded like a old 4 cylinder tractor motor with little to no throttle response. Now it responds instantly and has a totally different exhaust note. This engine runs and sounds awesome. Thanks guys!!!

 

[Don Jacks]

Your welcome,we all try to help,now about those Autolite carbs?How exactly did you set those up?

 

[Drive em]

I used a simple Mr. Gasket adapter from the Autolite carb to the Chevy manifold. The carbs are common 1.08" venturi diameter Autolites that are rated at 287 cfm. The center carb has a power valve and an accelerator pump, the two outer carbs have power valves, but no accelerator pumps. None of them have chokes because of space. All three of the carbs have the idle mixture screws as I like to be able to adjust the idle air/fuel mixture exactly as I want it. It runs awesome with progressive linkage that I fabbed up. The Autolite 2 or 4 barrel is the best carb ever made in my opinion, and I install them on lots of different engines.

 

[oldskydog]

Interesting. I was thinking about trying to use the two barrel Holleys from the Corvette 3x2's but it looks like the spacing won't work. I also thought about the common Furd Holleys and cut off the back of the air cleaner mounting flanges as it appears you have done.

 

[boxerdog]

That is pretty cool, and I'd guess that they might be less leaky than Rochesters.

 

[Drive em]

Interesting. I was thinking about trying to use the two barrel Holleys from the Corvette 3x2's but it looks like the spacing won't work. I also thought about the common Furd Holleys and cut off the back of the air cleaner mounting flanges as it appears you have done.

I would say that the Autolites are by far superior to the Holleys for a number of reasons, one being that there are virtually no leakage spots anywhere, and the venturi style is better than anything out there. Throttle response is nice and crisp.

 

[Don Jacks]

Those Autolite 's are,in my opinion,are the simplest carbs out there untill you get into the later "smog"versions.