Blown 408

I have an LQ9 that’s been prepped for 408 ci. It had 0.010 inch removed from the deck and bored to 4.030 inches with 4.0-inch stroke. I’ve had it assembled with Wiseco K464F3 pistons, and K1 Technologies connecting rods and forged steel crankshafts. The question I have is in regards to the heads. I have a Magnuson TVS 2300 out of a ’10 Camaro sitting on my bench waiting for a new home. I’ve a set of GM L92 ported #823 heads that I was thinking of using, but I’m unsure if these are the way to go. This is going in a lowered ’99 Z71 standard-cab Stepside with 285/50 R20 tires. Any information would be greatly appreciated.

Jim Moran
Via email

First, we think your Magnuson blower has found a perfect new home. Yes, the L92 heads are a perfect top end to round out your 408 short-block. These, with the blower, will easily make some serious power. You didn’t mention what you have spec’d out for the camshaft, but any mild blower cam will bump the power easily into the 600-plus range.

The only potential issue we noticed from your letter is that you clipped the deck 0.010 inch. Did you check the deck clearance with the short-block assembled? We just finished building our LS2 with a complete Callies 4-inch rotating assembly and Diamond pistons. After line-honing the block, we needed to clip the deck to square up the head surfaces. The machine shop removed approximately 0.010 inch, and when we got the short together, the pistons were coming out of the deck by 0.018 inch with no rock. The factory MLS head gaskets are 0.051- to 0.053-inch thick. We almost went for it because of the aluminum block; we knew the deck was going to grow. Thinking about it for a bit, we decided to have Cometic build some 0.060-inch head gaskets to ensure the pistons wouldn’t get too friendly with the cylinder heads. Your engine is an iron block and the deck isn’t going to grow. We’d make sure what your deck clearance is with your surfaced block. Please don’t run it any tighter than 0.038 inch!

Did you say you had a sponsor for those 285/50R20 tires? That engine is going to shred them, and they are far from cheap! Have a blast.

Source: cometic.com

Generation Serpentine

I have a ’69 Chevelle with a Mark IV 454 two-piece rear main seal. I have wanted to install a single serpentine belt system that would control power steering, alternator, and water pump, all in one. Being on a very tight budget, I cannot afford those very expensive aftermarket setup single serpentine belt systems. Even the GM single serpentine belt system PN 19172806 without A/C is out of reach. I am a firm believer of the wrecking yards, especially when they have their half-off sales. Could I use the serpentine belt system off a ’94 Chevy dualie 3500 with a 454 Gen V block on my Mark IV block? The water pump on the ’94 Chevy 3500 looks like it’s a long-neck, therefore I will be using the long-neck water pump on my two-piece rear main seal Mark IV. Could I use the power steering pump with hoses and the alternator on my ’69 Chevelle? I’m not sure if I could even use the alternator in my Chevelle. If not, what are my options, other than the pricey aftermarket setups?

Any help will be met with great appreciation. Keep up the good work.

Jose Rodriguez
Los Angeles, CA

Don’t you just love those half-off days at the self-service wrecking yards?

Yes, serpentine systems can be very pricey, and the GM alterative is much more affordable. If you’re scraping coins together to build your hot rod, the donor 454 Gen V front dress will do the trick. The GM kit is an assortment of production truck brackets and pulleys. Luckily, we strolled outside and checked out our ’93 3/4-ton Suburban with the Gen V 454 just like your donor. That drive system will bolt right onto the front of your early big-block. You must use the late-model water pump that matches the serpentine setup, as it is a reverse-rotation pump based on the belt routing. Your ’69 Chevelle has a standard-rotation, long-style water pump on it from the factory.