SSPerformance

iTrader: (76)

Going to get it dyno tuned in the next month or so on a dynojet just courious what kinda rwhp #s i should make heres the specs
454
10.5 to 1
Open Chamber ls7 Iron head
Cam specs: .574/.578 duration at .050 240/246 its a hydro
1.7 Roller Rockers
Single plane intake (Team G)
850 holley DP
Full MSD setup
going thro a TH400(3500 stall) and a 10bolt(my weakest link) 9in on the way


i just dont even have a clue where its gona be at.

slow trap

iTrader: (22)

the dyno will read your torque pretty close but it will probably read low on hp because of the stall.i'll say 450 tq 375 hp.or 450/425 if it reads right.this is an illiterate,uneducated guess of course.

SSPerformance

iTrader: (76)

i thought it whould be alot more then that

gator's 99TA

iTrader: (2)

power is made in the heads. lets talk about how well the heads and intake are ported and we can talk horsepower. also, that cam is quite moderate. what size headers? what are your goals?

this is why many old school guys dont like to dyno or talk about dynoing. since their drivelines are not dyno friendly. th400 and 3500 stalls arent the end of dyno racing but it could be worse. i am sure the track and street results are more important. dyno it and get back with us

SSPerformance

iTrader: (76)

The heads are LS7 heads that flow a lil beter then the LS6 heads that where ran on the LS6 SS 454 chevelle.....the car was advertised at 450 realy 500HP not rear whell but close

pwr2w8

I'll take a guess at 475-500hp and tq at the flywheel. 4500-6000rpm for the powerband. Again, a guess.

SSPerformance

iTrader: (76)

also cam makes power to 6500rpm

slow trap

iTrader: (22)

i was figuring around 550 -575fwtq and 525-550 hp.turbo 400s that arent race preped and non lock up stalls kill power,20-25 percent total drivetrain loss. my buddy dynoed his 383 sb and put down 425 tq but only 350 hp with a 3800 stall but it has atleast 500 fwhp.dynos are usually heartbreakers,especially slushboxes.

Racehead

I'm running pretty close to this setup except I have "049" oval port heads. 10 to 1 compression and a Performer RPM intake manifold. Do you have the Performer RPM cam ?? I do and the specs are the same ?? Anyway the results are in my sig. Once I get a few more small details ironed out I fully expect 430ish rwhp

pwr2w8

okay, but that doesn't necessarily mean the powerband does. I thought the powerband was the area between the peak torque and peak horsepower.
Upper 500's aren't likely with that cam and rectangle port heads(overkill). Port velocity slows down with larger ports, so you nave to rev higher to take advantage of that, but the cam doesn't.
It looks like a good combo though, you should take a couple small blocks with it.
I still say 475-500, and if it's a four bolt main spray it! An extra 200-300 hp can be easily had with that many cubes, as long as your bottom end is up to it.

Ratical

iTrader: (82)

By LS7 heads, I assume you mean 990 castings with 2.19in./1.88ex. valves and a 119cc open chamber? If no porting was done to these heads they will still work well, but if you get some extra money together for some port work, definately look towards the exhaust side. Bowl porting is always a great power maker too.

You didn't specify tube diameter on the headers, so I assumed 2" primaries. This combo should make around 500-525 flywheel hp and 500-525 flywheel torque. Take away parasitic losses from drivetrain and my guess is 370-380rwhp/400-425rwtq, (the flash spike reading should be higher, but not accurate.

An engine very close to that pushed my 3600lb raceweight 68 Camaro to 11.70s @ 117mph. I had a slightly bigger cam, 258/267 .588/.601 solid lifters, and slightly higher compression, 11.2 to 1. That was through a TH400 with a 3500 stall and 4.88's through the exhaust on street tires.

I'm not sure where middletown is, but that was at Lebenon Valley Dragstrip in Lebenon NY.

Have fun with it!

Tony Mamo @ AFR

iTrader: (13)

Actually, I think your guess will be very close to the mark.

I would say that flywheel numbers would be around 500 HP and 525 ft/lbs....back out 100 or so for driveline losses (auto and convertor) and presto....your guess is looking better than ever.

My .02 here....IF....(big IF)...the heads are unported, the low and midlift flow numbers are rather weak. The larger flow numbers up the scale (.700 +) you will never see so they don't even play into this picture.

What's even worse is the biggest problem with a factory BBC casting is the exhaust port....it isn't worth a crap. Our 205 LS1 head flows more on the exhaust with a 1.6 valve (no joke!) and kills it all thru the mid-lift #'s.

The manifold you have chosen will also cost you some power...its really never been a strong performer and the other BIG factor that will eat into your HP #'s are valve float....very common with BBC's and hydraulic rollers....the valvetrain on a BBC is VERY heavy and might start floating as early as 6000 RPM's....if so, you will see it in the dyno gragh and it will ultimately cost you power.

I hate to be a "killjoy" (whatever that is....lol), but it would be a better trip to the dyno if you went there armed with good information and a slightly less optimistic, possibly more realistic "guesstimate". Dyno's and Dragstrips can be a very "humbling" experience...set your goals low and you will always walk away smiling.

Again....JMHO

Good luck,
Tony M.

PS I hope I'm wrong and you make alot more....should be interesting results for sure.

SSPerformance

iTrader: (76)

the main reason im going to the dyno is to get it tuned... the heads are unported but i cant find anyone local to do some porting work. im also looking to go to a roller cam a lil bigger to take advantage of the stall. The headers are hooker Super comps. The Turbo 400 is a race preped trany from Pro-Built automatcis....my goals are a mid 11second run witht he current setup and i wana get in the 10s with a good port job on the heads

Patrick G

iTrader: (14)

Through a T400, you are probably looking at around 425rwhp.

PRAY HRD

iTrader: (119)

if possible, i'd stop right where you are. get the car itself dialed in. and then rather than removing the heads and having them ported, sell them for what you can, get a nice set of AFR's that have been cnc'd, and then change the cam and what ever else if it's a roller conversion. you're throwing your money out the window chacing after 10's and it aint gonna happen with that setup without spending some good dough on the port work. not too mention you'll realize a nice weight savings with the aluminum heads too. trust me, you will NOT regret it. otherwise, i sincerely feel you'll be very disapointed with the power, and you'll be wanting to do it soon enough anyway.

Dave

TTSSZ

iTrader: (8)

This can be a pain full subject if you have a old big block.
My 11 to 1 comp 427 w/ 425 hp was 425 at the crank.
On the dyno w/ no tune it did 350rwhp and 390rwtk thru a 700r4 non-locked and a 9" 3:50 rear. I was sort of depressed because I saw 02 camaro do 325rwhp the same day, bone stock....

Was so bumed I bought a 02 SS.
Well then twin turboed it. Did 327/337 stock and 572/550 turboed.

Now my plans are eather turbo the big block, or put a twin turbo ls6 / 6 speed into it. Im a old bbc dude from way back but a all aluminum light weight mouse motor may be in the workes for my 71 rs-z.
(I would do an Twin Turbo aluminum big block if I could afford it.)

PRAY HRD is right, the afr’s are the best heads on the market right know, I have a set of L-88 heads and a set of iron L-72 heads I want to sell, to get a set of afr's. If your #’s don’t make you happy, bbc’s love n2o I just put together a 200hp shot; to stay on par w/ my 02 TT SS