OK ive been trying to decide what to do for awhile now.. I know its time to upgrade the heads on my car and i wanna know the best way to go about it is. i wanna know if i should pick up a set 243's and get them ported or if i should just take my 853's to get ported? I plan on spending about $800. So if i get the 243's for about 400 and spend another 400 on porting will they outflow my 853's if i just spend 800 on porting those? the flow numbers im shooting for are 300+cfm on the intake side and 230+cfm on the exhaust side. Can 853's even be ported to flow that much? full details please
i know people are going to say just save up and buy TEA's or AFR's or PRC's, but i can get some 243's for pretty cheap and i really kinda wanna do this as an experiment.
keep in mind, i have NOT looked up porting prices, i know they are expensive but im just trying to get a feel for which direction i should head. If 800 wont get me the numbers i want( im pretty sure it wont) thats fine, then disregard the price ive put on it.
Last edited by Ryans99ls1; 11-06-2009 at 01:17 PM..
243's will slightly out perform 241/853's when both ported
__________________ 98 z-28,a-4,tr 230/224,comp 918's,ls6 intake+ported tb,Kooks 1 3/4,true duals with 1 chambers, pt4000,3.73's,spohn solids and some BMR susp.stuff.
best et=11.61 @116.30 on a 1.61 60'
you can find some used one's in the classifieds for 400-500. i paid $550 then sold the springs so i ended up paying $350 for the castings with valves. you can get new from SDPC for just over $600
__________________ 98 z-28,a-4,tr 230/224,comp 918's,ls6 intake+ported tb,Kooks 1 3/4,true duals with 1 chambers, pt4000,3.73's,spohn solids and some BMR susp.stuff.
best et=11.61 @116.30 on a 1.61 60'
243s will out flow and out perform 241s. I know this because I fought this battle. I had a set of 241's ported, deck milled .030, and 59CC chambers. I went with a different set of heads, 243s, cnc, ported, deck milled .005 and standard 64CC chambers with the same cam I gained 20rwhp with a larger cam I ended with 450+ rwhp on an A4 so that should tell you what a difference 243's make.
This is on an LS1 engine w/ over 80K on the clock.
243s will out flow and out perform 241s. I know this because I fought this battle. I had a set of 241's ported, deck milled .030, and 59CC chambers. I went with a different set of heads, 243s, cnc, ported, deck milled .005 and standard 64CC chambers with the same cam I gained 20rwhp with a larger cam I ended with 450+ rwhp on an A4 so that should tell you what a difference 243's make.
This is on an LS1 engine w/ over 80K on the clock.
So you put the 243 heads and a bigger cam on the engine at the same time?
Do you mean that stock 243's will out flow ported 241/853 heads. Or ported 243's will out perform them a little better.
the 243 is a better casting all around. if you port a 241 and a 243 the 243 will come out ahead assuming you have a head guy that knows what he's doing
__________________ 98 z-28,a-4,tr 230/224,comp 918's,ls6 intake+ported tb,Kooks 1 3/4,true duals with 1 chambers, pt4000,3.73's,spohn solids and some BMR susp.stuff.
best et=11.61 @116.30 on a 1.61 60'
If I was in this situation I'd take a 243 casting, cut a good valve job in it, do a good blend, deck them .015 and put it on the car. You can get this all done under $1000 (including the price of the heads) and have more compression than a 5.7L head, more piston/valve clearance.
I've done a couple of cars with 243's done the way I described, a custom cut cam, and normal bolt ons making 430-440rwhp with a nice flat TQ curve.
If I was in this situation I'd take a 243 casting, cut a good valve job in it, do a good blend, deck them .015 and put it on the car. You can get this all done under $1000 (including the price of the heads) and have more compression than a 5.7L head, more piston/valve clearance.
I've done a couple of cars with 243's done the way I described, a custom cut cam, and normal bolt ons making 430-440rwhp with a nice flat TQ curve.
this is exactly what i did. 243's with a hand blended VJ, throats opened to **% of the valve and blended. without the valvetrain i'm into them for $1200($350 for castings+$850 for the machine work)
__________________ 98 z-28,a-4,tr 230/224,comp 918's,ls6 intake+ported tb,Kooks 1 3/4,true duals with 1 chambers, pt4000,3.73's,spohn solids and some BMR susp.stuff.
best et=11.61 @116.30 on a 1.61 60'
If I was in this situation I'd take a 243 casting, cut a good valve job in it, do a good blend, deck them .015 and put it on the car. You can get this all done under $1000 (including the price of the heads) and have more compression than a 5.7L head, more piston/valve clearance.
I've done a couple of cars with 243's done the way I described, a custom cut cam, and normal bolt ons making 430-440rwhp with a nice flat TQ curve.
that sounds like a good plan. i still got a good amount of research to do but thats good advice.
Your best bet is to just save about $200 more and buy a set of CNC ported 243s. Texas speed starts with new castings, flow what you want, and are like $1025.
having someone port your heads isnt a good idea unless they flow them before and after to prove they didnt screw up their heads.
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Quote:
Originally Posted by John Lingenfelter
The world's best cam combined with a poor set of heads will produce an engine that's a dog. But bolt on a set of great heads even with a poor cam, and that engine will still make great power.
buy 243's or get mine ported? 
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