# ? about interchanging parts



## The Chosen One (Dec 8, 2010)

i am wanting to do wither 243 heads or 5.3's. along with the heads im wanting LT's and a fast intake. would i have to get ls2 LT's and intake mani or would the ls1 parts match as well. the reason i ask is because im not 100% sure which one will be ordered first. my ultimate goal is to reach over 400rwhp. my planned mods are goin to be the heads,kooks LT's,05-06 catback,fast 90 with ported throttle body, and a cam. the cam will be in the 228/230 with 112LSA area. then a good tune. sorry kinda 2 questions in one.


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## 87GN06GTO07IRL (Aug 10, 2009)

You can keep the ls1 parts. The ports will match.


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## The Chosen One (Dec 8, 2010)

so if i go with 243 heads then i will need the ls2 fast intake. does that also go for the 5.3 heads as well.


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## GM4life (Mar 18, 2007)

From the sound of it you have a LS1 correct? 243 heads are a direct swap on the LS1 no need to get a FAST or LS2 intake. 5.3 truck heads have the same port volume as the LS1 head with more compression. LS1, LS2 and LS6 are GEN III motors and have the same intake ports.


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## The Chosen One (Dec 8, 2010)

yes i have the ls1.im just wanting to make sure that if i have the intake and LT's for the ls1 and i switch out the heads to either 243 or 5.3 that i wont have to change intake or headers.


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## svede1212 (Nov 1, 2005)

Yup, the ports match up identically on LS1s & LS2s. I'd go with 243 heads which BTW were developed for the LS6. Our LS1 is basically an LS6 with 241 heads, a little different valves and a different cam that's why they fit our car . They were later used on the LS2 because they work so well. I'd also get them milled a bit (15-30 thousandths) and use a .040 Cometic gasket to get a good 1+ point bump in compression. That will also clean up the head and make it true. The compression increase will be good for 15+ HP all by itself. Using 243s milled .025 and .040 gaskets I'm running about 11.7ish to one compression. The tighter "squish" from using the thinner gaskets help get a better burn. Install a slightly colder plug like a NGK TR6 and get a good tune. I'd also do the cam at the same time to reap the benefits of the heads and only have to do it once (unless you tune yourself).

I'm not a big on getting a FAST unless you want to squeeze every last pony out on a LS1. It won't gain a ton over your LS6 manifold. Get your TB ported or something like a BBK 80mm and a bigger MAF. For the $1,400 for a FAST you get little bang for the buck. The LS6 mani is an excellent piece that only gets outflowed by the FAST up top and then not by a ton. For that money you can buy more HP elsewhere like getting the heads ported.

The cam is a big part of maximizing HP and the tune makes it drivable. My FlowTech Induction StreetSweeper HT cam, milled & worked 243s, BBK 80mm TB, my SS OTR intake, SLP LTs and a few other things got me over 450 RWHP.


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## The Chosen One (Dec 8, 2010)

looks like im goin o ditch the fast if its not as big of a gain over the ls6 intake. with the money saved there i can upgrade halfshafts.i was looking for 400rwhp but 450 would be even be better


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## svede1212 (Nov 1, 2005)

Get a LS1 2½" or 3" exhaust tho. If you have to have split pipes (I upgraded to a custom X with 2 ½" pipes coming out the same side) then get a SpinTech with the PFYC right side cutout piece.


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## dustyminpin (Jun 19, 2006)

Comp does not make a FAST 90 anymore. Everything is FAST 102 and they are still expensive. I paid 1000 for the LS3 version back in the fall of 2009 when they first came out. They are around 900 now. I think you can get the LS1/2/6 version for 850, still alot of money. High Performance Pontiac did a dyno study a few issues back on a bunch of different cams and used the stock intake and also used the FAST 102 intake. The FAST 102 is worth 14 rwhp over the stock intake. Is that worth 850-950? That's your call.


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## The Chosen One (Dec 8, 2010)

ok so looks like i will be doin 243's, keeping my stock intake mani, bbk 80mm TB, and ill get in contact with my tuning buddy about a custom grind cam,then doin a full tune.


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## The Chosen One (Dec 8, 2010)

spintechs are on top of my list when i upgrade my exhaust. however i prefer the sound from h pipes over x pipes.


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## The Chosen One (Dec 8, 2010)

what is the difference in the 59cc compared to the 64cc and i dnt see any difference in the stage2 and stage3 64cc heads.

Patriot Performance NEW GM LS6/LS2 Castings
* Fully Assembled 64cc Stage II Heads 650" Lift Springs, Titanium Retainers, Super 7 locks
* 21-4N Stainless Steel High-Flo 2.02"/1.57" valves
* 5 Axis CNC Ported, Polished Heads

PAT2013

$ 1249.99

Patriot Performance NEW GM LS6/LS2 Castings
* Fully Assembled 59cc Stage II Heads 650" Lift Springs, Titanium Retainers, Super 7 locks
* 21-4N Stainless Steel High-Flo 2.02"/1.57" valves
* 5 Axis CNC Ported, Polished Heads

PAT2029

$ 1249.99

Patriot Performance NEW GM LS6/LS2 Castings
* Fully Assembled 64cc Stage III Heads 650" Lift Springs, Titanium Retainers, Super 7 locks
* 21-4N Stainless Steel High-Flo 2.02"/1.57" valves
* 5 Axis CNC Ported, Polished Heads

PAT2015

$ 1249.99


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## svede1212 (Nov 1, 2005)

:cool If you get a good cam you should be be over 400


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## GM4life (Mar 18, 2007)

The Chosen One said:


> what is the difference in the 59cc compared to the 64cc and i dnt see any difference in the stage2 and stage3 64cc heads.


The 59cc and 64cc is the size of the combustion chamber. A 59cc head will have more compression than a 64cc head when used with the same pistons and head gaskets. Companies differ from "stage x" designation. Some the differences is the valve size, combustion chamber size, port volume size, and springs.


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## The Chosen One (Dec 8, 2010)

so i would rather bump my compression a little more. so if i went with a patriot ls6 head, and a cometic head gasket running a bbk 80mm Tb, with say a 224/227 with 114lsa cam. would those contradict in any way. and would that put me into the 400's


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## The Chosen One (Dec 8, 2010)

i think i found my heads. then have to find a cam to match the heads, keep my intake,possibly have it ported. 

Patriot Performance CNC Ported 243 LS6 / LS2 2.02"/1.57" 59cc Heads Assembled from Thunder Racing


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## GM4life (Mar 18, 2007)

You may be able to reach 400rwhp without high dollar heads. Custom grind cam with stock 243 heads should do you justice. Here in about a month or so I'm going to be doing a 243 head and cam swap on a C5 Corvette that we already installed "LS6" intake on. He may be able to hit 430rwhp in an auto.


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## The Chosen One (Dec 8, 2010)

ok so after the 243 heads,my intake will bolt directly up,and 04 kooks LT bolt up to 243 as well


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## GM4life (Mar 18, 2007)

Yes. 

243's have D shaped exhaust ports thats the only difference but the LT's will still bolt up.


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## The Chosen One (Dec 8, 2010)

sounds perfect.my parts list will consist of

patriot 243 heads 59cc
228/230 112lsa cam
cometic head gasket .040 3.901 bore?
arp head studs
ls1 kooks LT
factory intkae mani(ls1/ls6)
bbk 80mm TB

am i forgetting anything or listed anything that will not work


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## The Chosen One (Dec 8, 2010)

*which set of heads*

im trying to decide which heads would be better for my set up. im swapping heads into my ls1 gto as some may kno. im looking at getting the patriot 243's, but im not sure whether to go with 64cc or 59cc. if i go with 59cc the compression is supposed to be 11-1, and the 64cc is 10.5-1. if i run a .040 head gasket wil the 59cc be high to run with a mild cam soemwhere in 224/224 or 228/230 range.or what grind would better suite each heads. other mods are goin to be kooks LT headers,CAI,then everything will be tuned.


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## svede1212 (Nov 1, 2005)

It's better to have a thinner gasket than a smaller combustion chamber. The smaller "squish" area using a tighter gasket is what helps. I'm using a 61cc head with .040s for about 11.5:1. Some may depend on the gas in your area and also the cam. I can get 93 most everywhere and I'm using a 228/232 cam. Between your 2 choices you'd be either 11:1 or 11.8:1 with a .040. Given that I'd go with the 11:1 but if you could I'd shoot for something between those.


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## The Chosen One (Dec 8, 2010)

so with the 59cc using the .040 gasket ill be over the 11-1 mark,but what would i be looking at with the 64cc with .040 gasket. somewhere around the 11-1 im guessing.


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## svede1212 (Nov 1, 2005)

Yup. 64CC Would still be a 3-5% bump in HP just from the added compression point plus the added flow of the heads.. . They won't mill them to anything other than those two chambers? 61-62cc would be nice


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## The Chosen One (Dec 8, 2010)

ok so with the patriot 243 64cc heads, what size cam would give me that lopey idle and more gains across the board while keeping reasonable driveability.also would i still stick with 7.4 pushrods seeing how the heads come with patriot gold .650. the only other mods will be kooks LT's. and with the extra flow should i upgrade injectors.


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## svede1212 (Nov 1, 2005)

You should be close but OK with your injectors. If your duty cycle gets over 85% you can pop in some Ford green tops. They're a direct fit altho of course needing a retune. I'm very partial to my FTI StreetSweeper HT cam. It's a proven performer with our cars. 228/232 6.12/6.00 111 lsa. With the cam, those heads, LTs and a good tune you can pick up 100 RWHP as long as you don't have a bottleneck in the exhaust or cold air intake. 100 is a real kick in the pants.


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## The Chosen One (Dec 8, 2010)

currently there is a K&N on the car but i was looking at getting one of your custom OTRCAI,money allowing seeing how im building and paying the car off all in 6 months of time. but hey an extra 400bones, oh well. i still need to find a radiator cover as well. the car didnt have one when i purchased it. 

as for a bottleneck in the exhaust ima fraid you have me lost there. i know there is a set of cat back on there right now. im cant remember what they are but im pretty sure they are a knock off of magna flows. but im looking to do a spintech 05-06 conversion. that also depends on funds for when that happens. 

how is the streetability on that StreetSweeper HT cam?


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## svede1212 (Nov 1, 2005)

Your cat back is probably OK. I went an X pipe as it gives just a touch more HP and SpinTech muffs. You can just have the muffs bolted in to what you have. I;d wait until after you finish modding tho as your volume is going to go up a lot as it is. My cam is very tame. It's all in the tune.


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## GM4life (Mar 18, 2007)

I'm merging threads because you allready started one.


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## The Chosen One (Dec 8, 2010)

so here should be my final parts list, and i will probably contact someone on a custom cam for my setup 

patriot 243 64cc heads
cometic .040 head gaskets
7.4 patriot hardened push rods
kooks LT's
new timing set
arp head bolts
160* thermostat
diamond stage 2 clutch
crank pulley bolt

any gaskets or anythign i am missing or will need.can i reuse the stock lifters and trays?


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## The Chosen One (Dec 8, 2010)

the bore for the ls1 is 3.910 correct?


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## The Chosen One (Dec 8, 2010)

so using stock 243s with .650 patriot springs and .040 head gasket.will i need to change pushrod length or will the 7.400 still work with that set up. i am also considering changing lifters and may possibly go with the ls7 which i know i will need new pushrods for. and how would i find the correct length to use


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## GM4life (Mar 18, 2007)

The Chosen One said:


> so using stock 243s with .650 patriot springs and .040 head gasket.will i need to change pushrod length or will the 7.400 still work with that set up. i am also considering changing lifters and may possibly go with the ls7 which i know i will need new pushrods for. and how would i find the correct length to use


Pushrod length depends on the base circle of the cam. If the heads are milled or deck height also has an effect on pushrod lengh. To get correct mesurment a pushrod length checker should be used, you can talk to the manufacture for more info. All LSx lifters are the same. There is no such thing as a LS7 lifter.


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