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Old November 13th, 2014, 07:37 AM
hjennings hjennings is offline
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Join Date: Jan 2013
Location: Jacksonville, IL
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Age: 49
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Post Re: Forced Induction

I now have my own custom shop up and running. I do restorations as well as a lot of resto-rods. While a GMC V6 isn't going to be any big money maker for the shop, it is or sure on the to-do list.

Since the 305 is the most common we'll probably end up using one of those. I'm also thinking that the 305 will make the most power per cubic inch, being the larger engines don't really flow any better, so still bottle-necked at the heads. Plan on machining a custom camshaft, the intake will either be a custom one-off piece of have some serious machining and porting done to it. We'll do what we can with the heads as far as porting, but no matter what they are never going to flow "great."

Since these engines are so freaking heavy, we are hoping they'll be plenty strong for whatever kind of power we'll be able to put out. We'll lighten up the rods and crank some, polish, match weight, and balance it all. Pistons either stick with the 4-ring ones or maybe go with a custom made piston with a standard 3-ring setup (forged if we go that route).

Still in the bench planning stage, of course, but thinking of something around 8:1 compression, electronic fuel injection tuned for E85, a twin-turboo setup, a huge intercooler, and seeing how much boost we can run before something breaks.

We do a lot of work with internal performance coatings (like anti-friction coatings on the piston skirts, thermal barrier coatings on the piston faces, etc) so we'll use various coatings throughout the engine. I think getting the rotating assembly at light as we can without compromising strength will go a long ways. Might even go as far as to extrude hone the heads and intake (stuff is amazing, but still fairly expensive).

These engines are tanks. Way overbuilt on the strength side, so my thought is that it may really surprise us as to how much boost it'll actually be able to take and survive. I also think boost will overcome the lackluster flow of our heads.

Being this is such an unusual build I hate to even try and guess as to what the final horsepower/torque numbers would be. Stock they produced a whopping 120hp and 220ft/lbs of torque. I'm confident we can double those numbers! LOL! While I know these engines are strong and I'm confident they can handle some serious boost, I just don't know how much RPM they'll take before it's just too much. I think that'll be the biggest factor.

I'm going to make a wild *** guess that will probably be way off and say 15psi it'll make 500hp and 550ft/lbs in the 4000rpm range.
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