317 or 243 Heads?
317 or 243 Heads? I'm thinking about forging my lower end in my LS1. If I lower the compression with the pistons, what heads do you recommend? I have a set of stock 317's and a set of stock 243's. I know the 243's will flow a bit better. Thanks.
Well the 243's flow about 7-8% better than the 317's. That's from the flow numbers I've found online for both heads. I just couldn't remember if the 317's had a thicker deck?
I thought the ports were identical between the 317's and 243s with the Only difference being the cc's of the Combustion Chamber?
Can someone clarify this, please?
Also,
your LS1 is already @ 10:1 CR. If you use a dished piston, you'll most likely use the 243's because the other set will lower the CR substantially more. I'd just use the 317's because they Flow the Same/similar while dropping your CR as you want, leaving the 243's for sale with much more value.
Can someone clarify this, please?
Also,
your LS1 is already @ 10:1 CR. If you use a dished piston, you'll most likely use the 243's because the other set will lower the CR substantially more. I'd just use the 317's because they Flow the Same/similar while dropping your CR as you want, leaving the 243's for sale with much more value.
Get a piston w a dish. And valve pockets. Use a small chamber 243 head.
Wont have to worry about ptv and have a have some room for high boost w a dish.
If anything get pistons with valve pockets at least if don't want a dish.
Don't get the solid flat top pistons
Wont have to worry about ptv and have a have some room for high boost w a dish.
If anything get pistons with valve pockets at least if don't want a dish.
Don't get the solid flat top pistons
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I'm assuming money is a concern here? To get the best bang for your buck I'd sell the 243's and have a nice valve job and mild port work done to the 317's. You'll make more power in the end.
I will be running pump gas with meth. Do you think I will be able to get away with the flat tops? I think the -3.2 wiseco are around 10.1 with 65cc heads. I was thinking about those pistons with the 317 heads at around 9.5 comp.
I have two sets of 243 heads and a 6.0 with the 317's. I know the -11cc wiseco pistons are more than the -3.2 flat tops. I'm just trying to decide if I go a head and forge the lower end, if I want to drop the compression down to run the 243's since they do flow a little better.
I have two sets of 243 heads and a 6.0 with the 317's. I know the -11cc wiseco pistons are more than the -3.2 flat tops. I'm just trying to decide if I go a head and forge the lower end, if I want to drop the compression down to run the 243's since they do flow a little better.
I built an 8.6:1 5.3 and a 10:1 5.3. They ran within 2mph of each other at the track at the same boost level. Same car, same setup. I didn't mind the lower compression at all. The 10:1 motor was snappier NA. I'm well into boost before my car ever moves, so I could care less about NA response.
243 heads are overrated. Much like an LS6 intake manifold, 243’s sell for 3 times their worth. Sell the “magical” 243’s everyone is obsessed with and have your 317’s ported with a nice valve job and bigger SS valves. Then you’ll have a nice head that flows a LOT better than an untouched 243.
317 or 243 Heads? I'm doing very similar to what you just said. 6.0 LQ4 with H beam rods and JE forged flat top pistons with valve reliefs and 317 heads with new valve job. Comp with LS9 head gaskets is right at 10:1. Also using LS9 supercharged camshaft,LS7 lifters and comp cams 1.8 roller rockers.
I understand that. From a $ spent VS performance gained point of view… A 243 head makes no sense to me. Run the cheaper pistons and the 317 head to get your pump gas happy CR. The lower you go on the CR the more cushion you'll have for error in the tune. You trade NA response for in boost HP.
I built an 8.6:1 5.3 and a 10:1 5.3. They ran within 2mph of each other at the track at the same boost level. Same car, same setup. I didn't mind the lower compression at all. The 10:1 motor was snappier NA. I'm well into boost before my car ever moves, so I could care less about NA response.
243 heads are overrated. Much like an LS6 intake manifold, 243’s sell for 3 times their worth. Sell the “magical” 243’s everyone is obsessed with and have your 317’s ported with a nice valve job and bigger SS valves. Then you’ll have a nice head that flows a LOT better than an untouched 243.
I built an 8.6:1 5.3 and a 10:1 5.3. They ran within 2mph of each other at the track at the same boost level. Same car, same setup. I didn't mind the lower compression at all. The 10:1 motor was snappier NA. I'm well into boost before my car ever moves, so I could care less about NA response.
243 heads are overrated. Much like an LS6 intake manifold, 243’s sell for 3 times their worth. Sell the “magical” 243’s everyone is obsessed with and have your 317’s ported with a nice valve job and bigger SS valves. Then you’ll have a nice head that flows a LOT better than an untouched 243.
Pick a compression with works with the fuel you have available. I have 93 octane and meth with no corn available and I'm not shelling out for race gas on a street car hence my desired 9.4:1 static. Just build the whole combo around it with the correct cam, turbo, gears and stall (if appropriate) and it'll move.
Last edited by 97WS6SCharged; Jul 25, 2015 at 02:23 AM.
What are you guys running for compression? I was thinking around 9.5. I already have a alky control meth kit to install when I put the turbo on. For now I was hoping for 650-700hp. I have a stage 3 monster clutch, I plan on upgrading it when I upgrade the trans down the road. If I'm going to run the meth should I just go a head and run a little more compression?
What are you guys running for compression? I was thinking around 9.5. I already have a alky control meth kit to install when I put the turbo on. For now I was hoping for 650-700hp. I have a stage 3 monster clutch, I plan on upgrading it when I upgrade the trans down the road. If I'm going to run the meth should I just go a head and run a little more compression?
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i dont think anyone will disagree with that. its not unpossible it just narrows your margin for error. if you havent noticed theres alot of dumbf*cks doing this (including me).