[bluecar]

Need some help with my combination sbc 355 flat top piston ported vortec heads stock valves, guides cut for larger cam.
cam specs. 240/250 .521/.521 106ls
single plane intake 750 carb
turbo 350 trans 3200 converter with 3:73 gears with drag radials

Now here's the kicker 1993 silverado short bed.

How fast?

 

[Camaropwr]

I vote mid 13s on 125 shot of nitrous. Otherwise I'm thinking mid 14s.

 

[bluecar]

I was hoping 13s on the motor, the truck weight is 3700lbs with calvert bars

 

[Camaropwr]

Thats a lot lighter than I thought. You should get that if it leaves decent

 

[ten5nova]

Unless you're going to spray it a lot, I'd put more gear in the back.

Any pics? Sounds like a really cool truck!

 

[TomCombo]

I'd be interested in the results. I will say that it will run high 13's. 4.56 would help.

 

[bluecar]

Yes, its a cool looking truck. Should be up and running this weekend. Either my engine combation is off or something is really wrong. Why so slow???

 

[ten5nova]

Yes, its a cool looking truck. Should be up and running this weekend. Either my engine combation is off or something is really wrong. Why so slow???

That truck isn't exactly a fox mustang in the weight department, like we have said, go to a 4.56 in the back, that'll help a lot.

 

[TomCombo]

At that cubic inch and weight with a single plane, you will need more gear or more stall or both to do better than upper 13's. I had a milder 355 in a 500 lb lighter truck that went 13.7 with a 3.70 gear and 1.9 60'. Later it went 13.1 with a 4.56 and better traction aids, 1.7 60'. Same converter and dual plane.

 

[fastredgmc]

I have the same truck and same engine with a dual plane intake and smaller cam (224*/230*) went 13.80's. that was with 4.10s and 2800 converter.

 

[bluecar]

So many articles about the vortec going into the 12's at 3500lbs+ maybe I'm down on power or they're not telling the truth

 

[SB chevelle]

Another vote for performer rpm intake

 

[wrenchbender]

Another vote for performer rpm intake

I agree on this. Much quicker recovery on shifts. That manifold is hard to beat on any street small block, especially less than 400 inches, with a snug converter. JMO

 

[Mark J]

That should run easy 13s unless your at altitude.

 

[ten5nova]

cam specs. 240/250 .521/.521 106ls

I could be wrong, but that cam doesn't sound ideal for your combo...

 

[Matt Compton]

That cam and converter....14.20

 

[bluecar]

I was thinking the same easy 13's, I'm on the Eastcoast. What's wrong with the cam?

Solid lifter cam
240/250 521/521 106ls

 

[ten5nova]

What's wrong with the cam?

Solid lifter cam
240/250 521/521 106ls

Just doesn't sound ideal for a Vortec head, in my opinion. Might be a bit on the big side. Do you happen to have any flow numbers on your heads? Ported right? I'd talk with a manufacturer and see what they recommend for your application.

 

[bluecar]

intake 255 @ .525
exhaust 203 @ the same

 

[LTE008]

I don't think the cam is bad at all. I could be wrong though. More duration on the exhaust is a plus. Lift looks good for a vortec. The super victor vortec only loses 10ft lbs to a air gap rpm vortec but made 15 more hp. There is an article out there somewhere. They dynod them back to back.