L92 Vs. PRC 220cc 5.3L Stage 2.5 CNC Ported
02-02-2010, 10:39 AM
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L92 Vs. PRC 220cc 5.3L Stage 2.5 CNC Ported i need to make a decision on which heads i'm going to run. motor is a stock shortblock lq9 (flat top pistons). i will be spraying this motor. i would like to avoid having to fly-cut the pistons.
pricing would be as follows.
$1,134.99 for the ported 5.3 heads, + 60 bucks for upgraded valve springs. so $1195. everything i would need to run the l92's plus the heads would cost me $1559 (rockers, stands, hollow intake valves, locks, springs, retainers, seals, seats).
so, i would save $364 by using the ported 5.3 heads. another thing about the 5.3 heads, is they flow 223 cfm on the exhaust at .600 compared to the l92's 189 CFM (taken from the GMPP catalog), which i think will be better for spray, and help avoid having to flycut the pistons due to being able to have the exhaust valve closed longer. intake sides flow at 312 CFM at .600 for the 5.3, and 316 CFM for the l92.
seems to me the ported 5.3 heads are a better deal, unless the different style intake ports make that much of a difference.
i plan to keep the RPMs under 7400, will either style intake port hurt or help me? any opinions?
pricing would be as follows.
$1,134.99 for the ported 5.3 heads, + 60 bucks for upgraded valve springs. so $1195. everything i would need to run the l92's plus the heads would cost me $1559 (rockers, stands, hollow intake valves, locks, springs, retainers, seals, seats).
so, i would save $364 by using the ported 5.3 heads. another thing about the 5.3 heads, is they flow 223 cfm on the exhaust at .600 compared to the l92's 189 CFM (taken from the GMPP catalog), which i think will be better for spray, and help avoid having to flycut the pistons due to being able to have the exhaust valve closed longer. intake sides flow at 312 CFM at .600 for the 5.3, and 316 CFM for the l92.
seems to me the ported 5.3 heads are a better deal, unless the different style intake ports make that much of a difference.
i plan to keep the RPMs under 7400, will either style intake port hurt or help me? any opinions?
02-02-2010, 08:30 PM
#2
What are your HP goals?
Do you have an intake already, if not then it will not be a major difference in build cost or power either way.
Depending on the intended HP, I might reconsider the use of a hollow stem in a nitrous/boosted application.
Unless you use a big cam with a tight lsa, flycutting will not likely be needed with either head. You will of course have a bit more room with a smaller valve setup though. My 238/242 cam on a 115lsa had a mile of room.
I happen to have a set of L92's with stainless/inconel valves and PRC .660 springs for sale with only dyno time on them for $999 with rockers and stands.
https://ls1tech.com/forums/parts-cla...ers-999-a.html
Jim
Do you have an intake already, if not then it will not be a major difference in build cost or power either way.
Depending on the intended HP, I might reconsider the use of a hollow stem in a nitrous/boosted application.
Unless you use a big cam with a tight lsa, flycutting will not likely be needed with either head. You will of course have a bit more room with a smaller valve setup though. My 238/242 cam on a 115lsa had a mile of room.
I happen to have a set of L92's with stainless/inconel valves and PRC .660 springs for sale with only dyno time on them for $999 with rockers and stands.
https://ls1tech.com/forums/parts-cla...ers-999-a.html
Jim
02-02-2010, 08:42 PM
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well, i already ordered the 5.3 heads. if i would have seen your post earlier i might have reconsidered, but it's too late now. i'm just trying to get a 2800 pound car with driver into the low 10's on motor, spray it well into the 9's. i don't think it will be that hard with the 5.3 heads. it will be going through a th350 trans. i'm not sure on what cam i'll run. i've yet to call vengeance racing, but i was looking at their 240/244 .605/.596 112 LSA cam, and the 238/240 .605/.609 112 LSA cam. also considering just getting a custom. i'll call them and see what they say. but anybody should feel free to give me their opinion.
also think i'm going with the victor jr. intake. car will be carb'ed.
also think i'm going with the victor jr. intake. car will be carb'ed.
Last edited by R0B0T; 02-02-2010 at 08:48 PM.
