243 heads
09-14-2010, 11:38 PM
#1
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243 heads I've got a friend selling 243 ls6 heads with prc .650 double springs. How much more power would that produce over stock ls1 heads? Would they be able to support an ms4 cam?
09-14-2010, 11:43 PM
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Are we talking ported or non ported?
I'd say a conservative guesstimate would be about 50 hp at the rear wheels, maybe less, maybe more. What cam do you plan on running with it if you do get it? How much is he willing to let them go for?
Edit: Disregard question number 2. I reread and noticed you wanted to run an ms4 cam.
I'd say a conservative guesstimate would be about 50 hp at the rear wheels, maybe less, maybe more. What cam do you plan on running with it if you do get it? How much is he willing to let them go for?
Edit: Disregard question number 2. I reread and noticed you wanted to run an ms4 cam.
Last edited by Z28_LT1; 09-14-2010 at 11:48 PM.
09-14-2010, 11:59 PM
#4
just an FYI i made 395 rwhp on a mustang dyno with a cam... I added stock LS6 heads and a FAST 90/90 and put down 430 rwhp and close to another 45 ftlbs with those 2 items.
you'll probably pick up anywhere from 15-20 rwhp
YOU ARE NOT getting 50 rwhp with stock 243s... conservative?!?!??!
you'll probably pick up anywhere from 15-20 rwhp
YOU ARE NOT getting 50 rwhp with stock 243s... conservative?!?!??!
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09-15-2010, 05:28 AM
#9
15-20 max on unported 243's. The ms4 lift is .649 IIRC so you are right at the limit.....I would pull a couple springs and check pressures... IMO that is not a very good DD cam because of the very agggressive lobes which are tough on springs, valve seats etc...
09-15-2010, 08:14 PM
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just an FYI i made 395 rwhp on a mustang dyno with a cam... I added stock LS6 heads and a FAST 90/90 and put down 430 rwhp and close to another 45 ftlbs with those 2 items.
you'll probably pick up anywhere from 15-20 rwhp
YOU ARE NOT getting 50 rwhp with stock 243s... conservative?!?!??!
you'll probably pick up anywhere from 15-20 rwhp
YOU ARE NOT getting 50 rwhp with stock 243s... conservative?!?!??!
That's why I was asking about the cam, but I forgot to change the number. whoops. 
09-16-2010, 09:22 AM
#13
What is the rest of the setup?
What year is the engine? If it's a 98 you might squeeze out a couple more hp. I would guess around 20 total.
Why do you think you want a ms4? If you have to ask about 243 heads I would venture to guess you have a lot of reading and learning to do rather than just sticking in one of the biggest off the shelf cams that fit and hoping for the best. If you're combo isn't right that cam will run like **** even if it does throw down high dyno numbers.
Don't forget you are going to need pushrods, ls2 timing chain, upgraded oil pump, most likely larger injectors, gaskets, fluids, and head bolts.
A dyno and street tune will be mandatory.
If you're an auto a 4000+ stall will be mandatory and deeper gears in the rear.
If you're manual you will need 4.10s minimum.
And with either you will need headers, exhaust, ls6 or better intake, and lid minimum to support the heads/cam.
What year is the engine? If it's a 98 you might squeeze out a couple more hp. I would guess around 20 total.
Why do you think you want a ms4? If you have to ask about 243 heads I would venture to guess you have a lot of reading and learning to do rather than just sticking in one of the biggest off the shelf cams that fit and hoping for the best. If you're combo isn't right that cam will run like **** even if it does throw down high dyno numbers.
Don't forget you are going to need pushrods, ls2 timing chain, upgraded oil pump, most likely larger injectors, gaskets, fluids, and head bolts.
A dyno and street tune will be mandatory.
If you're an auto a 4000+ stall will be mandatory and deeper gears in the rear.
If you're manual you will need 4.10s minimum.
And with either you will need headers, exhaust, ls6 or better intake, and lid minimum to support the heads/cam.
09-16-2010, 09:38 AM
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I just put ported 243's with stainless 2.055/ 1.57 valves on my ls1. I do have the ls6 intake and a cam, headers, intake, and exhaust. I am expecting 35 rwhp gain or so. Its going on the dyno later this evening so ill post back and let you know. But 15-20 rwhp sounds about right for stock 243's on an ls1.
09-20-2010, 08:16 AM
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I just put ported 243's with stainless 2.055/ 1.57 valves on my ls1. I do have the ls6 intake and a cam, headers, intake, and exhaust. I am expecting 35 rwhp gain or so. Its going on the dyno later this evening so ill post back and let you know. But 15-20 rwhp sounds about right for stock 243's on an ls1.
09-20-2010, 09:55 PM
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I bought them from hutter performance. They said they were ported by C.F.E. They were milled .005 just to remove a scratch on them. I will say that before them my p/b on motor only no n20 was 12.700. After them I ran a 12.277. In addition to the heads I had put on a monster level 4 lightflywheel, solid motor mounts, and qa1 adjustable drag shocks since the 12.700. I do attribute most of the gains from the heads. 14 rwhp was depressing to see, but I was happy to be in the low 12's on motor. Should take me from high 11's on spray to low 11's. Maybe 10's by next year. Pretty good for a goat
