Im getting ready to put my 305 back in, and wondered if i would get much from swapping to a l98 head. I know the l98 has a bigger combustion chamber, but how much bigger?? Will the increase of valve size make up for the loss in compression? It will be breathing much better now that i ditched the TPI in favor of a LT1 intake, and swapped out the small headman LT's for some Hooker SC LT's. I know it sounds overkill for the 305, but thats just temperary till i get some heads for my 406.

Thanks, Curtis

 

You'll lose a bunch of compression and I dont think you will make it up with a .1" valve difference. The runners on the L98s are slightly larger though, but really to get the most out of the L98 heads you gotta run normal compression. You could always get them milled.

 

You would lose alot of compression, and the valves would hit th cylinder walls due to the smaller bore. If your looking for some heads, either go with World S/R Torkers, or L98 Aluminum Vette Heads.

 

Why would the valves hit the cylinder walls with iron L98 heads and not with L98 Aluminum ones? They're almost identical heads.

Have you seen 2.02/1.6 heads on a 305? They dont even come that close to hitting the walls when you look up from the crank valley.

Common myth #1: 2.02/1.6 heads cannot fit on 305s.

 

Talk about contradicting yourself

 

1. L98 aluminum and irons are not nearly identical.
2. Aluminums have 58cc chamber just like 305 heads
3. Iron L98 heads have about 64cc (if I remember right)
4. They both have 1.94" intake valves (if I remember right)
5. Edelbrock says you can run a 2.02 intake valve head on a 305 safely up to .450" cam lift.

 

1. Lined up beside each other the exhaust and intake runners are almost identical. Differences are the angle plugs and the aluminum material.

2. Yeah they're 58cc like the iron 305 heads. The reason there is the difference between the cc in the iron and aluminum because of the heat loss in the aluminum. Less cc makes up for the loss in heat.

3.Yeah they do

4.Yes they do

5. Edelbrock says you can, but in actuality, you could run up to .550-.600 before shrouding even becomes an issue. The biggest issue is the fact the 305 doesnt need 2.02/1.6 valves when everything else on it is stock.

RMK, how did i contradict myself??

 

Maybe I read your post wrong. But what it came across as was that you were saying first of all that the valves don't come close to hitting the walls. Then the next thing you were saying is that it is common myth that 2.02/1.6 valves can't fit on a 305. That's one thing then the other.

Or were you just pointing out a common myth and I did infact read it wrong?

No flames intended.

 

Yeah ok I was saying that 2.02/1.60 dont come close to hitting the cylinder walls so they do fit...

then I said that it was a "myth" that they cannot fit. I was tryin to point out a common myth because 2.02/1.60 heads can fit on 305s but most people dont think they can