The top end of my LG4 305 is shot. I have the opportunity to buy the top end off of a ZZ4, Including: Alum. Heads, cam, lifters, pushrods, valvecovers, timing chain and alum. intake manifold. Will I be able to put these parts on my LG4? Are the heads drilled for my existing alternator and A/C brackets, and power steering mounting?

What will happen to my compression?

Thanks for any help

 

I assume you mean the '84.

The heads will fit, but there will be some issues. The '84 LG4 used dished pistons and steel shim head gaskets with 58cc heads. The ZZ4 heads are 58cc, but being aluminum, you can't use steel shim gaskets. Your compression will be lower than 8.5:1, and being aluminum, you want about 9.5:1 or more. So, power will be down.

The cam won't fit. It's a roller, your '84 is flat-tappet. Forget all of the ZZ4 timing components for your engine.

The valve covers fit the heads, so that's not an issue if you put the heads on your engine - they won't fit your current heads, though. The intake will fit. The heads are drilled for your accessories.

 

Ok, thanks for the info.

I kind of thought the compression would drop.

Any advice on what type of head gasket to use?

Also do you know if the heads can be machined to raise the compression back up into the 9.5 range without milling the intake manifold?

Im only asking because I can get a pretty good deal ($) on these heads.

Thanks again, I appreciate it.

Yes I did mean the 84 T/A.

 

In order to get that kind of compression with dished pistons by milling, the intake will have to be milled as well.

You probably don't want to hear this, but your best bet would be to get a roller 350 block to use with all those ZZ4 parts. That would make it a really good buy. And idea.

The '84 LG4 shortblock just isn't a good base for building a performance engine. The ZZ4 parts you're talking about, with a 350 shortblock, would work nicely with the LG4 carb system, though.

Don't forget exhaust. And air cleaner. Both would be too restrictive for use on that system.