66oldz

Can I assume that starting with a block that has not been decked I can go to stock length push rods, lifterS and new cam? The lifters are .921 and the push rods are 9.4375 (7/16).

If I go to a bigger cam will I have to change the length of the push rods.

how do I measure the cam to see if it has the correct lobe size. There is no abvious wear on cam.

Lonnies Performance

If staying with an OE style lifter & relatively mild cam which also uses the factory base circle dimensions, then yes it should use the same factory length push rods.

It is always worth checking the rocker to valve stem alignment & lifter preload once the cam is installed just to be sure, but it should be OK.

66oldz

I plan on using the new roller rockers purchased for these new aluminum edlebrock heads. Will this make a difference. I have checked and the rods coming out of the engine are .4375 I. Length and the engine calls for a stock length of .4450. Would the rods still be good to use or are they too short?

Run to Rund

It would be safest to mock up one pair of lifters (I and E) with rockers, etc. before installing the intake. Verify that the pushrod cup in the lifter is depressed .010" or somewhat more when the lifter is on the base circle of the cam.

OLDSter Ralph

Have you tried to identify what cam you have in the engine now ?

66oldz

I do not know how to ID the cam. Any suggestions. The person I bought it from a wife of someone who passed away so I can’t get any information on the cam etc..

OLDSter Ralph

Look on the end of the camshaft for any numbers. Right now, you have no idea what cam you have and therefore, no idea if you could go bigger (more duration or lift).

Schurkey

NO. Seems like EVERYTHING affects proper pushrod length. So the block has not been decked. How about the heads? Were the valves refaced, and the seats cut? If they didn't trim the valve tips, the valve tips are now too high. Different rockers change proper pushrod length. Thinner or thicker head gaskets can change proper pushrod length. Any one of these is probably not enough to require a different-length pushrod, but add several variables together and they can. Pushrods are the LAST thing you buy when assembling a long-block.

What you have in your favor is that with the stock Olds valvetrain, pushrod length affects ONLY lifter preload. If the lifter preload is where you want it when you assemble the long-block, you're set. The Chevy guys have it tougher, because with an individually-adjustable valvetrain, pushrod length affects valvetrain geometry.

If you had a Chevy or some other engine with adjustable valvetrain, the ONLY way to know for sure is to mock-up the valve train and examine where the rocker is riding on the valve tip. In a perfect world, it would ride dead-center, with minimal sweep as the valve opens and closes. Since this isn't a perfect world, it's better to have minimal sweep even if that means being somewhat off-center. And in mocking-up and examining, don't forget that hydraulic lifters will probably collapse (leak down) during the process, so be sure to compensate for that. But that's not going to be an issue for you, if you have an otherwise-stock rocker system.

Lobe "size" is a matter of base circle, plus lift. Base circles vary. Base circle is important for determining pushrod length--but that's included in the overall results when you mock-up the valvetrain and look at lifter preload, or with a Chevy, the sweep at the valve tip after the desired lifter preload has been set..

66oldz

The engine is such:
The heads are brand new edlebrock aluminum
The rockers are brand new steel roller rockers

I would like to keep the cam but I don’t know how to measure because I don’t have the measurements. Do I measure the lobe?

the same thing with the crank shaft. How do I find the measurements for the journals so I can purchase correct bearings?

the push rods are stock and are the correct length - this I have been able to check and double check.

svnt442

OK....with the aluminum heads you will not be able to use stock rockers (already stated that you're not) so you WILL need custom length pushrods....the cam won't matter in this. You have adjustable rockers and this will require you to measure the pushrod length needed by following the above instructions.

Schurkey

Get a degree wheel and a dial indicator and base. You'll need to measure crankshaft degrees from TDC Compression #1, and lifter rise. Together, you'll map the intake and the exhaust duration at .006, at .050, and the amount of peak lift (and the crankshaft degrees that peak lift occurs at. When you're done, you'll compare your results to fifteen different cam catalogs, until you find one that matches.

Then you know what cam you have. Unless what you have was custom ground, in which case it won't be in a catalog.

And yeah, with Edelbrock heads, you're doing the "Chevy" pushrod checking procedure--looking for minimum sweep at whatever lifter preload you think is proper; keeping in mind that the hydraulic lifter is going to collapse.