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Old 02-07-2013, 10:01 PM
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cobalt327 cobalt327 is offline
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Originally Posted by vaughn bros View Post
Colbalt327 Thanks again. We decided to go with the pull the manifold and do the lifters job. I am still trying to figure out what engine specs I have. The engine block number is 3782870, its got 350?, heads, and I dont know whats inside. Last week it ran like a 60's rail dragster. We **n luv it and dont want to damage it.

I think I will get a full set of lifters at the Chevrolet dealership. I also saw a little bit of damage on 2 pushrods right at the oil hole so they will get replaced too. But I wonder if I should loose my cast iron intake and go to aluminum? I like the cast iron intake.

Also about the vacuum for the distributor. There are two ports I question. My distributor is hooked up to "A". Should it be hooked up to "B" instead? Thanks.
OK, just saw this. Before ordering up a set of lifters that you may not need, get the one bad one out and take it apart and see what you can see.

I would much prefer you to use just the plunger from a new lifter in your old lifter body (replace the guts, in other words), than to try to get away with using a new lifter (or a set of new lifters) on a used cam. Fixing the original lifter by cleaning is the best case. Next to that, replacing the guts of the old lifter, then next would be to use only ONE lifter to replace the unrepairable lifter. Last choice, and one I just cannot recommend under ANY circumstances, is to replace ALL the lifters with new ones.

The reason is pretty simple, really. If one lifter is replaced, only one lobe and one lifter will be ground up into the motor oil to act as sandpaper to ruin the engine. If the entire set of lifters are replaced, the chances are more than one lifter and cam lobe will fail, and the amount of sandpaper in the engine will be a lot greater.

If it turns out that the bad lifter is trashed on the bottom where it contacts the cam, consider the cam trashed, too. In that case, replace the cam AND lifters as a set. It sounds expensive, I know. But it's less expensive than replacing the lifter(s), then having to tear the engine back down again to clean it of the ground up metal caused if/when the cam and lifter fail, then having to replace the lifters a second time along with a new cam, including another set of gaskets and more oil and filter.

BTW, be sure to use this link to the page on taking the lifter apart.

An aluminum intake would be a good addition to your engine. Especially if you're using an adapter to mount a Holley carb on an intake made for a spreadbore Q-jet carb.

If your truck has a mild cam I might go with an Edelbrock Performer EPS (p/n 2701 for satin finish, for '86-back heads).
If the cam is bigger, I'd use a non Air Gap Edelbrock RPM (p/n 7101, satin, for '86-back heads).

BUT before buying an intake, you need to see what heads you have. The bolt holes changed on '86-'95 heads, then again on '96-up heads.

Having 15 inches of vacuum could mean you have a bigger than stock cam, or it might need more initial timing. It might even have a vacuum leak. Does it have a "lope" to the idle, or is it very smooth?

You are hooked up to ported vacuum. It might run better using manifold vacuum (the vacuum port on the baseplate). Try it and see. The problem is sometimes the vacuum advance gives too much advance. Usually 10 to 12 degrees added vacuum advance is about right if you're using manifold vacuum and a good amount of initial timing. It won't hurt to try using manifold vacuum, though. You will find that it will increase the idle speed, so be ready to lower it and to readjust the idle mixture screws to get the highest idle speed, or highest vacuum if you have a gauge.
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