LT4 question

[snaggeltooth]

this is what has been done to it ..
Engine:
-355 LT1 w/LT4 Hotcam, stock heads, and 1.6RRs
-Racetronics 32# injectors, 52MM TB w/ airfoil, K&N CAI
-EWP, Underdrive pulleys, MSD Coil, Taylor 8mm wires
-Pacesetter LTs, Custom 3'' exhaust w/E Cut-out and Dynomax Ultra-Flo
So how much HP you think that is making over a stock LT1 and how much would worked heads help.???
Ohh it has had a custome tune at a local shop ...

[5.0THIS]

Through a 6 speed... 330-345rwhp.

[side2000]

you'll gain some substantial gains from LT1 to 4 heads, those LT1 valves are pretty small. the LT4 heads still aren't that great, some aftermarket heads or some ported LT4's with big valves would be the way to go.

[snaggeltooth]

LT4 heads would = how much $$ .. Would they be a basic bolt up ??

[side2000]

well to buy them from GM is too much for what they are. i think a set is 14-1500 from summit. they would be basic bolt-up but you need LT4 manifold unless you wanna modify the one you have (not worth it). what's your budget look like?

the LT4 heads would be a good base for the cam you have, but respond better to a little work, they have 2.00/1.55 int/exh valves which could stand to be replaced.

[snaggeltooth]

well to buy them from GM is too much for what they are. i think a set is 14-1500 from summit. they would be basic bolt-up but you need LT4 manifold unless you wanna modify the one you have (not worth it). what's your budget look like?

the LT4 heads would be a good base for the cam you have, but respond better to a little work, they have 2.00/1.55 int/exh valves which could stand to be replaced.

with waht 5.othis said .. 350 RWHP is a good place to be for me .. vs at least $1200 ... thanks for the info ..

[5.0THIS]

porting the LT1 heads is a better bet than trying to get LT4 heads.

[Cayenne97]

porting the LT1 heads is a better bet than trying to get LT4 heads.

IF...money is an object. If money isn't, LT4's will give you more flow and more power over any built LT1 - period.

[5.0THIS]

IF...money is an object. If money isn't, LT4's will give you more flow and more power over any built LT1 - period.

If I was that concerned with an extra 10-20 cfm that the LT4 heads offer over LT1 heads at any given stage, I wouldnt be fucking around with factory heads anyway.

[Cayenne97]

If I was that concerned with an extra 10-20 cfm that the LT4 heads offer over LT1 heads at any given stage, I wouldnt be fucking around with factory heads anyway.

GTP LT4 race heads flow about 320 cfm out of the box. Show me an LT1 head that is within 10-20 cfm of that. Fully ported LT1 heads flow good, but not as well as LT4's. LT4's have the potential to make more power in a higher range.

[grandkodiak]

lt4 hot cams kinda soft especially if you are gunna stroke and get decent bottom ends that can handle some extra rpms

[5.0THIS]

GTP LT4 race heads flow about 320 cfm out of the box. Show me an LT1 head that is within 10-20 cfm of that. Fully ported LT1 heads flow good, but not as well as LT4's. LT4's have the potential to make more power in a higher range.

I probably would never run a factory casting head CLAIMING to flow 320 cfm. I'm betting they're paper thin. Besides, put those GTP heads on several different flow benches and I bet they dont flow 320. Simply, I dont believe their heads flow that well.

And like I said, if I wanted to make that big of power, I'd have a thick deck ported AFR head and boosted motor and be done with it. 99% of people just wont see the added benefit of LT4 over LT1 heads.

[bigrondownhiller]

GTP LT4 race heads flow about 320 cfm out of the box. Show me an LT1 head that is within 10-20 cfm of that. Fully ported LT1 heads flow good, but not as well as LT4's. LT4's have the potential to make more power in a higher range.

At what lift do they flow that?

[Cayenne97]

I probably would never run a factory casting head CLAIMING to flow 320 cfm. I'm betting they're paper thin. Besides, put those GTP heads on several different flow benches and I bet they dont flow 320. Simply, I dont believe their heads flow that well.

GTP heads have always lived up to their claims and are arguably what some consider one of the top LTX heads on the market. And what would lead you to believe their flow numbers are bogus? Sounds pretty wacky if you ask me.

99% of people just wont see the added benefit of LT4 over LT1 heads.

Probably because 99% of people won't choose to take an LTX that far naturally-aspirated. But some will. I have a few friends myself that have, N20LT4 being one example that made well over 500rwhp naturally-aspirated with a set of 227 LT4 heads. LT4 > LT1.

At what lift do they flow that?

.600.

[5.0THIS]

Probably because 99% of people won't choose to take an LTX that far naturally-aspirated. But some will. I have a few friends myself that have, N20LT4 being one example that made well over 500rwhp naturally-aspirated with a set of 227 LT4 heads. LT4 > LT1.

Yeah, and if I wanted a good head I'd go with an AFR aftermarket head, because they have more potential. At that point who gives a fuck what LTx port it is.

[side2000]

Yeah, and if I wanted a good head I'd go with an AFR aftermarket head, because they have more potential. At that point who gives a fuck what LTx port it is.

oo, i care ,i care!

[N20LT4]

N20LT4 being one example that made well over 500rwhp naturally-aspirated with a set of 227 LT4 heads. LT4 > LT1.

Yup, 509rwhp w/ 215cc runners (not 227, damn Cayenne ). That car was a blast to drive, amazing midrange and top-end pull!

[side2000]

Yup, 509rwhp w/ 215cc runners (not 227, damn Cayenne ). That car was a blast to drive, amazing midrange and top-end pull!

what size bottom end? redline?

[N20LT4]

what size bottom end? redline?

It was a 385, just under 7000.

[side2000]

very nice.