Hot Rod Forum banner

Carburetor size? And which Oil to use?

2K views 6 replies 6 participants last post by  richard stewart 3rd 
#1 ·
Ok two questions:

I rebuilt a 402 engine in my 1972 Chevrolet Cheyenne PU truck. Bored 60 to 4.185 and hi rise Eldebrock Performer RPM intake. headers, Comp. cam .498 intake and .483 exhaust lift. Roller 1.7 rockers. Steel crank, balanced everything! Large oval port heads that have been ported to match intake gasket, not polished. The casting number on the heads come up as a 427 425 head. The only carb I had to run has a number on the frt of 60570, 3460. I was told that it's a 570 cfm. I have been building engines since I was a teenager but that doesn't mean I know all bout tuning an engine or carbs. This engine runs great but it sure seem to be wanting more gas. What size carb do I need to make this engine come alive?

Next question, I built this engine with the Joe Gibbs grease called Driven and Royal Purple oil and Royal Purple oil filter. I did the 2500 RPM for about 20 minutes or so at start up and all seem good. I have only about 300 miles on the engine so when do I need to change the oil and what would be a good oil to use? This is the first engine I've built in a few years so I'm not use to the Zink and what every else was taken out of the oil. Sure glad I did some research before building.
 

Attachments

See less See more
1
#2 ·
Hi
You'll need at least a 750 cfm or a Q jet (I like Q jets)
After the break in run, did you change oil & filter & open the filter to see what's there? Anyway, the oil your using RP is very good, you might consider using it all the time, also you have a roller set up so you need not worry so much about what was taken out of most oils. I would change oil & filter at about 5K
Best of luck:thumbup:
Rich
 
#3 ·
X2 on the Rochester Q-jet.

I have a 1962 Chevrolet Bel Air 2-door sedan, 4-speed with a 327/300 engine. The original 650 CFM Carter AFB needed to be rebuilt (restored) and after comparing prices, I changed to a stock GM 1966 intake manifold, a Autoline rebuilt Rochester Q-jet and a '66 air cleaner and still came out a $150 winner. It did not hurt the originality of my '62 Chevy much because you can't see the 750 CFM Q-jet lurking under the air cleaner.

My 327 engine was bored .030" OS and completely rebuilt in 1986. I broke it in on Valvoline 10w-30 Conventional All Season motor oil and about 1993, I switched to Valvoline VR-1 10w-30 Conventional motor oil that includes 1480 PPM zinc. My 1962 heads were then equipped with GM Z28 valve springs at 90 lb seat pressure ans 280 lb open pressure at .447" valve lift. I did a valve job again a year ago and instilled Pioneer/Elgin VR943X valve springs that were set up at. 1.700" with 130 lb seat pressure and 300 lb open pressure at .447" valve lift. I saw no evidence of wear or recession on any of the valve seats and no cam wear on the camshaft that was installed in 1986.

I give credit for the lack of valve train wear to Valvoline VR-1 Conventional motor oil in the Silver bottle.
 
#5 ·
have to wonder why use expensive oil just to dump out after cam break in. i would have saved the RP for after that. other poster putting the zinc oil in AFTER cam break in? got it all backwards Homer. zinc goes in first. THEN you can get rid of it and use regular oil.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top