[Painstain]

Hey guys!

I hate adding to the list of "Critique My Build!" Threads, but I'm currently deployed to Iraq and can't bounce ideas off of the one SBC guru I know.


The 383 SBC will be going in an early 80's Chevy K10 w/a TH350 and 4.11 gears (if you think a different gear would work better, please say so). I want to use the truck for Daily Driving, and light off-roading (trail riding, light mudding, forest service roads, etc.). I'm trying to make the motor a "Stump Puller" with as much <3000rpm torque as possible and still run on 87 Octane.

I have a budget of around $5k (give or take $1k), but would like to keep the cost as low as possible.


-SCAT Rotating Assembly w/ Flat Top Pistons
-Dart Iron Eagle Heads (180cc Intake, 72cc Combustion, I/E Valves 2.02/1.60, 1.25" Valve Springs)
-Comp Cam X4280HR (PN: 12-414-8) - (Not sure if this cam will work, I had it picked out for a different build)
-Edelbrock RPM Intake
-Holley 750CFM (PN: 0-3310S)
-Hedman Headers, 1 5/8" Primary x 3" Collector (PN: 69090)
-3" Y-Pipe (if I can find one) to single 3" exhaust && Magnaflow 3" Cat w/3" Glasspack




This build is still in the R&D stage, I currently have the 350 block and Scat Rotating Assembly and will start purchasing other parts once I'm stateside (coupla months).

If I left anything out, please let me know - and thanks for reading!
-Austin

[Painstain]

Forgot to add:
Cam is a Hydraulic Roller, 280/284 Duration - 230/234 @ .50, w/ 111 LCA & 107 Intake Centerline.

Truck's gonna be wearing 35's w/a 6" lift.

[V8 Super Beetle]

Looks good to me. With your parts you should have around 9.8:1 CR and a DCR of 8.3. I would guess about 450 hp /450 tq.

[ericnova72]

With 35" tires a 4.56 or even 4.88 gear would be a much better choice.

[Painstain]

I appreciate the numbers, SB. Those numbers (TQ/CR) are about where I want them.

Eric, thanks for the suggestion. I guess I should have done a bit more research into gearing.



-Austin

[ballsout1]

i`ve got a gm truck on 35`s with a 700r4... i pull 2200 rpm @ 65 with 4.56`s. with a turbo 350 i would guess you would be at 2800 or so. that would be more in line with your power curve. really depending on your drive i would use 4.88`s how often is that truck gonna be @65?

[Painstain]

Originally Posted by ballsout1

i`ve got a gm truck on 35`s with a 700r4... i pull 2200 rpm @ 65 with 4.56`s. with a turbo 350 i would guess you would be at 2800 or so. that would be more in line with your power curve. really depending on your drive i would use 4.88`s how often is that truck gonna be @65?

After doing a little bit of reading, I'm thinkin' 4.88's too.
65-70mph is normal in my daily commute.


Also, Does anyone have recommendations for stall speed? Stalls are one category that have me pretty confused. The cam I plan on running has an RPM range of 1800-5800 and recommends a 2500 stall. I've read a couple (unofficial) places that a 2500 stall works well with non-race trucks - so that's what I was thinking of using..

[Painstain]

Or maybe a Yank Truck Thruster 2600 Stall?



(Sorry, I can't edit after 30min )

[ogre]

save your money.
2 1/2'' duals all the way.
3'' y-pipe system will cost you more than 2 1/2'' duals all the way out back
more flow, less cost, better sound.

[techinspector1]

I'd be thinkin' 5.13 gears. Here's why.
The cam calls for 3.73-4.10 gears. This is with a standard 28" tire. Just for grins, let's say 3000 rpm's with a 4.10 gear and 28" tire. The speed is 61 mph. Now, let's change out the tires for a set of 35's and change out the gears for a set of 5.13's. The speed is 61 mph.

I'm using the high side of what the cam calls for gears because of the way the OP is going to use the truck.

Oh, and by the way Austin, thank you very much for serving. I'm very proud of you.

[Painstain]

Originally Posted by techinspector1

I'd be thinkin' 5.13 gears. Here's why.
The cam calls for 3.73-4.10 gears. This is with a standard 28" tire. Just for grins, let's say 3000 rpm's with a 4.10 gear and 28" tire. The speed is 61 mph. Now, let's change out the tires for a set of 35's and change out the gears for a set of 5.13's. The speed is 61 mph.

I'm using the high side of what the cam calls for gears because of the way the OP is going to use the truck.

Oh, and by the way Austin, thank you very much for serving. I'm very proud of you.

5.13 Gears actually make a lot of sense when you put it like that.. Keeps the mph/rpm ratio the same - right?

I really appreciate the support, Tech. It's an honor to serve - and it's people like you that make this country worth fighting for.


-Austin