LT4 aftermarket heads for an LT4 turned 383 stroker

[jcook00]

What are the best aftermarket heads for an LT4 turned 383 stroker motor. a friend of mine has a 2000 LS1 with an MTI 406 stroker. He keeps telling me I would come out way ahead with an LS1 motor versus the LT4 that is in my 96 vert. He says he went from stock 345 fwhp to over 450 rwhp with just heads and cam. Then got stroked + 150 shot nitrous for over 600 rwhp in a daily driver. Given that he spent over 8K to get their, what is the most cost effective way to get an LT4 to make 450 rwhp? I have no aversions to aftermarket parts since that allows me to store my orginals intact. I don't want to put an LS1 in my LT4. Similarly, I don't want to spend thousands to mod LT4 heads if aftermarket heads can get me their for less.

 

[sothpaw]

I think my heads guy would port LT4 heads for $1500. A ported LT4 head would be killer. I'm sure you can do better than 1500, but this was a very respected place. You pay for the name.

 

[CKA_Racing]

Are you concerned with passing emission testing? That would affect how you would approach the build. Even so, 450 RWHP with just heads and cam on an LT4 is not that easy to do. Keep in mind the LS1/LS6 heads are a more efficient design. They have taller runners and that's part of what makes these heads capable of having slightly more power. You can't modify an LT4 head to be as tall, it's impossible. So your buddy is some what correct. On a stock cubic motor, the are almost the same as far as HP.

Take a look at this site.
http://www.moreperformanceinc.com

It is possible to make sick power with an LT4, but it will cost you some money and involve more that just a head/ cam change.Will also more than likely no pass emissions testing either.

Look at the package at MORE and you'll see kind of what I'm talking about.

The LT4 450HP package will gave you around 370RWHP.

 

[Shriker]

LT4's are plenty capable of producing 450 rwhp in modded form. Honestly , the LS1 is only slightly better in all out capability. The LS6 is better still (its heads are a notch up on even the LS1's).

As for heads/cam cars , good LS1's make about 425 rwhp, good LS6's about 450 rwhp. A good LT4 can make around 415+ rwhp, not that far off.......

I have seen plenty of LT4's make 450-500 rwhp , usually 396 strokers with highly worked stock LT4 heads, on pump gas. If you want, you can buy aftermarket heads that when worked will match or exceed LS1 heads and therefore make as much or more power, AFR makes a some good ones for example. A solid roller cam helps quite a bit as well .....

It would be silly to go LS1 if you already have an LT4 unless you just want the newer design. The LT4 can produce competitive power .......

Good luck

 

[inferno-vette]

AFR's 210 is the head you want. Have'em slightly ported/polished with some pocket porting and these will outflow ported LS6 heads, as for a cam, get a CC306 and that alone will get you into the 400's rwhp, then you can get a stroker if you want.
BTW longtube headers, a good exhaust (B&B or Corsa), along with a 52mm throtle body is a must for a motor like this.

 

[Hutch]

What about "standard" CNC LT4 heads? I'm running a set of these on my stock displacement LT4 with More Perf top-end kit and have been happy with them but wonder if I need to rework them when I go for that 396 stroker block?

Last dyno was 364 RWHP with heads, cam (222/230), 52mm TB, 30# injectors, long tubes, power effects, and FastChip program.

I want an honest 450 RWHP but in a streetable package. My current cam has a slight lope which is fine, but I'm not willing to give up my drivability for the biggest numbers.

Suggestions???

 

[1996man]

when we are talking about head flow can we measure it in numbers like cfm? that way we know what we are comparing to what. i know that a good shop can get over 300cfm out of stock LT4 heads easily and that is a lot more than a lot of aftermarket heads flow