June 2010 Chevy High Performance Letters - Performance Q & A

Tom Truty May 5, 2010 0 Comment(s)
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Hopefully, the mail-order sites won't be upset that I've sent them a potential customer. You never know what else you need once you get there. My biggest complaint is that once I've confirmed an order, I always remember something else I needed. There goes the shipping and handling again! Sources: dougherbert.com, jegs.com, summitracing.com

Filter/Regulator Follies
Q: On page 43 of your Nov. '09 issue, when you were modernizing your '72 Nova, you mentioned using a '99-and-newer fuel filter/regulator combination. Can you write out the instructions as to which fuel line goes to which outlet on which end of the filter can? Thank you very much.
Larry Van Unen
Priest River, ID

A: The filter you're talking about is the filter/regulator combo that GM used first in 1999 on LS1-powered Corvettes. This unit was put into service when GM converted the engine to a single-line, returnless fuel system. The fuel filter/regulator is mounted back by the tank in the original application. For our swap application it allows you to install this filter right at the tank, or in front of your high-pressure pump. This eliminates that hassle of running a return line the length of the vehicle.

The filter has three ports: two nipples and one female pushlock connector. The inlet feed and outlet returns are the nipples, and the regulated outlet is the female connection. The inlet from the pump is the 3/8-inch nipple on the perimeter of the end cap of the filter. The 5/16-inch outlet return comes out of the center of the same end cap of the filter as the 3/8-inch inlet. On the opposite end of the filter you have the one 3/8-inch female port that is the regulated outlet port of the filter.

This extremely inexpensive combo part is very handy for plumbing up EFI fuel systems. The regulated fuel pressure is 58 psi constant, and there is no vacuum bias in the fuel pressure from this type of regulator. The GM part number for this is 10299146, and the ACDelco (usually a bit cheaper) number is GF822

Deluxe Hop-Up
Q: I have a 350 H.O. Deluxe GM Performance 330 HP Engine. Can I put on the ZZ4 aluminum heads and feel a significant difference? Will it be worth it, or should I put in a cam and the heads?
Chevy High Follower
Via email

A: The 350 H.O. Deluxe comes equipped with a pair of Vortec iron heads and an updated 350hp, 350-cid, hydraulic flat-tappet camshaft. This is a great base engine that performs very well. If you were to swap to the aluminum L98 Vette (ZZ4) cylinder heads you'd realize minimal gains. The iron Vortecs are based on the iron LT1 heads, which are quite a bit better than the L98s. They would give you about 10 hp from the CR bump. Now, if you wanted to give the ZZ4 heads a quick port job, which entails bowl work on the intake, and throat, bowl, and guide boss work on the exhaust, you can see around a 30hp gain with the heads. The beauty of the ported heads is that they kick out some killer torque numbers. The small inlet runner makes these heads really work. We'd take these ported heads and swap them onto a ZZ4, then stepping the power numbers up into the 380hp range, but the torque would climb into the 430s. This would really wake up a ZZ4.

If you're looking for more power, swap out your camshaft for a hydraulic roller. The H.O. Deluxe block will accept '87-and-up roller hardware. The Lunati Voodoo PN 60121 would be a great fit. This camshaft is designed for an LT1/LT4 EFI engine package, and specs out at 219/227 degrees of duration at 0.050-inch tappet lift, 0.515/0.530-inch max lift, ground on 112 centers. The idle quality would suffer slightly, and you'd need a 2,200- to 2,400-stall converter, but this would really wake up the Deluxe, especially if you port those ZZ4 heads, pushing the horsepower well into the 400 range and keeping everything happening under 6,000 rpm. Source: lunatipower.com


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