I hope you guys will bear with me; I’m new to supercharging and this board.
I have a 1990 454SS pickup. About 2 years ago I found a Vortech supercharger kit for it. As is common, plans and free time change. I was working on another project and it kind of sat for a while. The other project, a 1974 Vette, hit a snag but I already had the engine built. So I dropped that engine, a 496 in the SS for a while, it was making 578hp and 588tq at the flywheel.
While the 454 was out of the SS it was rebuilt with forged pistons, Edelbrock TBI cam, intake and headers. A set of slightly worked GM 781 oval port heads top off a 4 bolt block with pretty good rods and ARP bolts with a cast GM crank. I think I can live with the cast crank due to the low rpm, under 5,000.
It’s a lot stronger than I thought it would be! Stock the 454SS only had 230hp and 385tq with max torque at 1,600 rpm. Friends with similar mods are getting around 320-350hp and 430-460tq at the rear wheels. I was not sure how much the Vortech would add. I think it’s faster in the 1/8th than the 496 was! Granted the 496 needed a 3,000+ converter and I was running a 1,400.
It ran really well no the trip home, about 400 miles at 65-80 mph and has not set any codes. It’s only making about 5 psi boost and I’m letting it shift it’s self at around 4,500 rpm, I think it’s pretty well done by then anyway.
I am having two problems! Belt slip and fuel leaking around the TBI shaft.
I have ordered a new crank pulley, 8.5” vs. the stock 7.5”. On the SC I’m planning to us a 3.12” vs. the stock 2.87”. I hope this will reduce belt slippage as well as provide a little more boost. Stock compressor speed at 5,000 rpm is 45,022 the new pulleys will up that to 46,920. Is this a problem?
For the problem of fuel being forced out the TBI shaft (I think it’s only happening during deceleration) I plan to add a second bypass valve close to the SC outlet. We tried a Mondo race type bypass but it was slow to close, I think it was just to big!
Thoughts?
Al 454SS/SC
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