Where do I go next??????

[americanmusc1e]

OK, for lack of a better way to say this, I will list my specs. Please tell me the things that are slowing me down the most. starting with the cheapest to fix first.

Would anyone here use nitrous on this engine???? (I have my entire savings into this engine and I can't affford to break it.)

any ideas on what rpm to shift at???

is the stock HEI slowing me down????


Engine:
.060 over 350 4bolt block
Scat cast steel 3.75 stroke crankshaft
Eagle H-beam rods 5.7
Hyperecutec Pistons
Vortec heads (home ported)
Comp cam .477/.480 lift 224/231 duration @ .050
stamped steel 1.6 roller rockers
1 5/8 headers, full dual exhaust
Weiand Stealth Vortec Intake
Holley 600cfm VS 4160
stock HEI dizzy

Transmission:
700r4- built with shift kit and upgraded cutches and bands
2000rpm TCI converter

Rear End:
not totally sure on the gears, 3.08 or 3.42 open diff

Tires:
Maxxis Mudder 31", a little stickier than a street tire (but I still do one-wheel burnouts for 100')

Chassis:
stock
rancho RS-X shocks

Body:
stock '70 LWB fleet
approx 4200lb

I'd like to throw on a pair of AFR 195's and a bigger cam (THUMPR 287??), and pick up another 75-80 hp, but that would cost way more than I can afford.

[Wild83C10]

Why do you say something is slowing you down?

Looks like a good combo to me, but the "mystery rear" would be the first thing I would figure out.

[Jim_PA]

The holley 600 on your 383 has to go!

[ProStreet71]

Not sure how you intend to drive your truck, but with that big of a tire you need more gear. Like a 4.11 or even a 3.73 since you have the 700r4 with the lower 1st gear. But a good posi and some better tires will definitley pick your times up, cuz if your spinning you aint moving. Doesnt matter how much power you have if you cant put it to the ground. A little more stall would prob help too.And in my opinion I would not use the spray on those hyper pistons. Hope this helps....

[Wild83C10]

I don't think the 600 is hurting you. I wouldn't go any bigger then a 650 anyway.

I am with Prostreet on this one, the gearing is probably the killer.

[Marv D]

I agree, looks like a nice street combination. I'd check into gears and see, but I also wouldn't get too crazy being a 700r4. That 3.06 first gear ratio of the 700 is the deepest 1st gear of any of the GM automatics. You better have GOOD traction if it's going to bite the track with a low gear rear end. But that's pretty much all been said.

If you are bit by the faster faster faster bug,, the vortecs (especially with an unproven port job) have to go, as does the flat tappet hydraulic cam.

Decent heads (Brodies or AFR 195's,, or something equal), a nice hydraulic roller (or solid roller if your so inclined) will give you tire shreading power on that 383. Then you'll be wishing for more gear and something with less 1st gear ratio. It's a never ending battle.

[americanmusc1e]

thanks for the replies!!!!

I don't want to do any major changes to the truck, (besides the gears) I just want to make sure my combo is working together as efficiently as possible.

after careful consideration, I don't think the 600 Holley is slowing me down, Why, because I don't run the motor any higher than 5500rpm. using the standard carburetor cfm calculator--even at 100% VE it still comes out at 617cfm

what about the stock HEI, Is it holding me back??????

I also plan to get the truck dynoed soon.

[scatesracing]

The stock HEI could a little but at 5500rpm i doubt it... My last stock hei would fall on its face at 6000 or so. i put in an accel module it would fly right by 6000 after that..

[ProStreet71]

Really not much point in doing anything else to the engine or otherwise if you dont want to make the changes to hook it. More horsepower will just = more tire spin. There is really nothing wrong with your combo, looks like a great recipe for a nice street motor. Getting your carb and ignition curve dialed in on a chassis dyno will possibly net you a few more horse, maybe even 20 or more depending how far off your tune may be, if at all. Ok with that bein said, dont put too much faith in the actual dyno numbers because alot of them are really conservative and may lead you to think that you arent makin the power you should be. But, they are a great tool for tuning.

[djracer]

The dyno numbers will hurt your feelings. They did me with my old street truck.

[KQQL IT]

I agree Dynos hurt egos But good for tuning.

[68 C-10 KID]

Originally Posted by KQQL IT

I agree Dynos hurt egos But good for tuning.

I 3rd that motion.

[americanmusc1e]

Originally Posted by KQQL IT

I agree Dynos hurt egos But good for tuning.

yeah,

I've been helping with some dirt track cars around here (nearest dragstrip is too far away for that kind of fun every weekend). Some guys I know, (not our car) had one of the cars dyno-tuned. the initial pull was 80hp, with ignition timing set properly it did 115, and when they got the 2barrel dialed in they had 216hp.