So I'm in the middle of building my 370 right now for my 99 rcsb truck. It's got a 80 swap with a 3600 circle d stall & 4.10 rear gears.
I'm trying to see if I should do a good cathedral port or ls3 top end.
I'm going to be spraying a 150 shot on top but wanna make all I can n/a also.
Oh yea it's got neg 2 cc pistions. I was told it should be 10.8 to 1 with stock 243 heads.

Thanks for any help.

 

I went square port for the flow. I'm running flat tops with valve reliefs. Should be 11.5 to 1

 

can I ask what kinda power you got out of it? Also any track times?

 

Just got my build completed last week. Should be taking to the tuner this week and he'll have it for a few days so he can tune the nitrous but as soon as I get a power number I'll post it on this thread for you. Also, should be getting some 1/8 mile track times in the next few weeks.

 

Our build is very similar. We're shooting for 460-470 n/a.

 

Hmmm... not sure thats correct. I have 69cc heads (LS3's stock are 68) with 3.2cc valve relief pistons and its a 10.2 compression motor.

You really cant go wrong with either option, but if I was building NA only and had a big budget I would choose a nice set of cathedrals. With a smaller budget I think the LS3 head starts to look really attractive. It likely wont quite have the snap of a nice cathedral, but it will pull hard as hell from your mid range on up.

 

I've really been thinking ls3 due to being to get a pair of full heads for 650. Then thinking milling them down some to the compression up around the 10.8 .

 

For the money the GMPP CNC ported LS3's are a very pretty head.

 

This to me comes down to budget and desired compression ratio.

 

Could you explain a little more ?