Cascade Crew

91RSVert · Posted: Mon Sep 09, 2013 4:59 pm Post subject: Head help

Ok, likely to get you lost here, but hang with me.

Jimmy I think has rounded off a cam lobe. So I am replacing the block with a roller.

I plan to get a set of L31 vortec heads(63-64cc?) and put on the camaro that currently has aluminum 113's(58cc). Now Ive read with alumn heads, you have to go to a smaller cc to make them same as iron. So will this effectively leave me "the same compression"? Will my pushrods be the same length?

Now, the block I'm getting is one that needs rebuilt. I was told it came from a tbi truck. Should the pistons that came in it work decently with the 113 heads? Or should I up the compression? I want to run this on 87 pump gas, with hei ignition.

In the jimmy, heavy 4x4, carb, hei, roller. What cam would you suggest? (I know next to nothing about cam selection).

chevymad · Posted: Mon Sep 09, 2013 6:00 pm Post subject:

Aluminum transfers heat better then iron. This allows you to up the compression without getting detonation. No hot spots.. However, since it's pulling heat from the combustion chamber it also lowers the amount of power. So usually the higher compression vs the power loss is about a wash.

There's no way to know if your pushrods will be correct or not. That's just about the last thing you can do when assembling. Motor will have to be all together and then you measure and order the correct length

Are the pistons dished? If not I don't think you'll make your 87 octane requirement. What's your elevation there? Here at sea level I got away with dished pistons and 64cc iron heads using 87 octane. If you're higher elevation you can get away with more compression. There's just less air going in the cylinders. This of course will also depend on the cam you choose. A cam with a large advertised duration can help you get away with more compression. Torque type cam (XE or Voodoo grinds) will detonate easier.

If you're rebuilding anyway.. I'd buy pistons to get the compression ratio required for the cam you choose to run the correct rpm range for your vehicle... See its all tied together.

aaron_sK · Posted: Mon Sep 09, 2013 7:55 pm Post subject:

chevymad · Posted: Mon Sep 09, 2013 8:09 pm Post subject:

Pistons for a 350 cost basically nothing anyway.

91RSVert · Posted: Tue Sep 10, 2013 4:04 am Post subject:

So as for putting the vortecs on my camaro. Your saying I should be good to go compression wise. Esp since I got it with irons(810's), switched to alumns(113's), now going back to iron.

So, as to the block I am getting. I havent seen it, wont see it tell this weekend, delivered to my driveway. My general elevation is 335ft. As for towing, I WAS thinking nothing more then empty trailer around a yard, or with mower. But If I'm 4x4'ing, I may have to tow someone out a hole. So I guess I will be. But if I'm doing that, I will know and can put some higher octane in it.

So cams. I have an lt1 in the camaro. I guess I could get a slightly hotter one for it, and put the lt1 in the jimmy? I'm not opposed to buying nicer stuff for the camaro, and using "leftovers" for the jimmy.

aaron_sK · Posted: Tue Sep 10, 2013 9:26 pm Post subject:

Hmm...

I'm doing a bad job of following this build.

When you first built this truck you wanted to use it to replace your 1-ton diesel rig and tow a car trailer.

Also a woman would never drive it.

Now you just want to tow a lawnmower.

If this is just a beater wheeler then you don't have to be as picky.

But you open up more options for driving style. Are you wide open through mud holes at redline or lugging it in double-low over rocks?

Also, will a woman ever drive it? Razz