RockyMtC5

one year ago I had a mild head/cam done and decided to wait on intake and kept my rusty 1 3/4" headers. Results were 406 rwhp and 370 ft/lbs.

Recently my headers started cracking and leaking where they bolt to the bell housing, time for new headers. Just ordeee American Racing 1 7/8" catless headers and Xpipe. I also bought a used FAST 90 and LS2 throttle body with the adapter harness. I took it apart and completely cleaned it up, bought all new gaskets and hardware and am going to ask my builder to port match to the heads (milled PRC stage 2.5 6.0 liter heads). Also have a catch can (elite) & Fast 36# injectors. He will install everything and dyno tune. I'm hoping for 430rwhp & 400tq. Thoughts?

Itll be a a few weeks but I'll keep you all posted. Here is my current dyno graph

00__Vette

It'll be interesting to see what gains you get. Post them up after you get them. And do you think the 1 7/8 headers will make a significant increase over the 1 3/4 headers?

SPEED750

I would say you should get there . Not sure about the injectors, factory ones can go a long way. As long as your tuner figures them in you'll be fine. A lot of people just buy bigger injectors and install them. Then they run way rich and have black exhaust tips.

RockyMtC5

I'll post the dyno graph when it's done!
My builder thinks I'll pickup a bunch with the bigger headers for these heads, and I'm hoping he's right.

Tuner is good so if he says I don't need the injectors we'll skip them

493lszosix

430/380 just my guess, I think the intake will gain you some hp but tq probably won't change much but it will be interesting to see the results!

RockyMtC5

I'll take the 430 but hoping for a little more torque..... I'll post results in a few weeks!

ZZOOM06

Just an FYI, when I went to an unported Fast 90 and 1-7/8" ARH headers on my old H/C LS6 RWHP went from 430 to 455 and RWTQ went from 401 to 435. Heads were ported and milled LS6 and the cam was a 232-236*
.595"/601" on a 114+4 LSA. I was running 30# SVO injectors at the time, so I do highly recommend that you change out your stock injectors as they will exceed their duty cycle. IIRC, compression ratio with that set-up was right at 11.5 to 1.
Hope this helps,

Jimbo

RockyMtC5

thanks, If I get similar results I will do back flips!!!

i have lower compression for sure, 10.5:1 probably so my torque will probably stay lower but I'll be happy with 385+ foot pounds but I definitely want 430 rwhp and I'm pretty sure I'll get it.

headers should arrive this week and I'm hoping to have everything done and dyno tuned by Halloween

RockyMtC5

Headers still haven't shown up but should early next week. I dropped off my car with the parts yesterday and should have it back next Friday! I hand ported my FAST intake and sanded off most of the wedge in the runners that everyone gets rid of. Blended everything else and polished it up.
My builder thinks we can get 30-35 hp and that would put me right where I wanna be.
I'll post the new dyno as soon as I get it, so hopefully a week from now

RockyMtC5

My builder called and told me everything is done and street tuned, with the dyno tune scheduled for tomorrow afternoon! Can't wait!

He did say he's feeling a big SOTP gain and is thinking 35-40 RWHP gains...... I hope he's right. I'll post up after the dyno. I'll also scan the new dyno sheet in as soon as I can.

It's supposed to snow tomorrow, hope it misses us and doesn't ruin my dyno day!

C5 Pete

Cool. Looking forward to the results.

RockyMtC5

Results are in, I gained 28 hp and 27 tq- pretty much hit my goals right on the head!! Very happy

RockyMtC5

On the dyno, first run was the best

CorbinC5

Nice looks c5

ErikwithAK01

6 speed? Or a4

almosttherec5

glad to see mid to low 400's are possible with simple bolt on's like this.. new to vette (came from a termi)

corvet786c

Nice flat torque curve between 4500-5500 rpms.

Good results