305 Heads - Third Generation F-Body Message Boards

TJ07RK · 11-06-2009, 06:23 PM

A few people have told me the stock heads on my LG4 will work on the L98 and are better then the ones on the L98 now. My question is this true and would they be worth the effort to put them on? Also if this is true will a LT1 hot cam work with the 305 heads without much work?

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five7kid · 11-07-2009, 11:57 AM

They are no better than L98 heads. They have the same ports but smaller combustion chambers and intake valves. If you put them on a stock L98 they would raise compression to about 10:1, which is a bit high for pump gas premium, but reduce flow and most likely overall power.

In order to work properly on an L98 with an LT4 Hot Cam (there was no LT1 Hot Cam), you would have to have 1.94" intake valves installed, clean up the ports & bowls, polish the chambers, have the valve guides cut down (prepping them for positive-type stem seals is a good way to kill two birds with one stone), and replace the valve springs and retainers. Plan on nothing but the best premium gas you can find for the rest of your life.

TJ07RK · 11-07-2009, 01:12 PM

Sorry about the LT1/LT4 I know better, don't know what I was thinking. I have just had my head in LS1's for about 10 years now. Tring to get back to the basic with these older engines.

So would it just be better to fix up the L98 heads or are the LG4 heads worth the effort?

five7kid · 11-07-2009, 03:45 PM

Depends upon what you're after. The L98 heads would need the same guide/spring work, and would benefit from the port/polishing work.

The bigger cam would help bleed off some of the higher compression with the 58cc chambers, but you'd probably be better off overall with the L98 heads.

TJ07RK · 11-07-2009, 06:15 PM

I think I am going to stick with the L98 heads...

five7kid · 11-08-2009, 01:47 PM

That's probably the smart move. The 305 heads are a good choice if you're starting with a truck 350 with deep dished pistons and you won't be changing the pistons.

TJ07RK · 11-09-2009, 10:20 AM

Quote:

Originally Posted by five7kid

That's probably the smart move. The 305 heads are a good choice if you're starting with a truck 350 with deep dished pistons and you won't be changing the pistons.

Well I am not planning a piston change yet, but the longer I mess and have this car the more I plan to do to it. The good thing is the 305 in the car now seems to run fine so I have lots of time to work on this 350..