[GTOKIDRH]

Originally Posted by Skip Fix

A summit 2801 is pretty mild in a low compression 400 also -one in my 81. degreed right on the button also dot to dot.

I've actually already started seriously considering the 2801 over the 2800. Thanks for the info! Can you offer a y more feedback on it as well as the specifics on your ride it's in?

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[SD455DJ]

Originally Posted by GTOKIDRH

I've actually already started seriously considering the 2801 over the 2800. Thanks for the info! Can you offer a y more feedback on it as well as the specifics on your ride it's in?

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GTOKIDRH - Here are actual dyno results of a '78 W72 400 with 8.75 to 1 static compression ratio. It was a fresh rebuild and used the Summit 2800 cam like you may be considering:

"Dan had a good dyno session today with the W72 400. This is the original numbers matching engine that was removed way back in the late 1980's to make way for an SD455 build with a Doug Nash 4+1 5-speed trans. The original owner of the car rebuilt the W72 engine in 1980 with an H-O Racing TurboForce system and went to .030" over TRW's on SD455 forged rods. When the Mike bought the car in the mid 1980's he immediately went to work pulling the turbo'd 400 and building the SD455 engine.

Long story short, Dan rebuilt the original numbers matching engine with .040" over Icon forged pistons w/4.5 cc valve reliefs that are .006" out of the hole and with .045" x 4.328" Felpro head gaskets to provide .040" quench depth. The 6X-4 heads were minimally cut for trueness and measured 92.45 cc's average for a final static compression ratio of 8.75 to 1. Dan replaced the cast rods with forged Eagle H-beam rods. New 1-pc valves (2.11/1.66) with CC dual springs were installed. A Summit 2800 cam (204/214/114 @ .422”/.444”) with new 'old' Crane hydraulic lifters along with a new Melling 60 psi oil pump. The one modification was the use of old factory D-port ram air exhaust manifolds with the 2.1" outlets with Pypes 2.5" mandrel headpipes. The original 17058263 Q-jet on the factory cast iron intake with the EGR system and plumbing were reinstalled.

The base runs were made with 42 degrees total timing in by 3000 rpm, 45 primary rods/74 jets/CH secondary rods on an I hanger. The 3rd (and best) base pull made a corrected 360.3 hp @ 5000 rpm/456.1 lbft torque @ 3600 rpm (351.2 hp/444.5 lbft uncorrected). The correction factor was a low 1.026 as the weather conditions were very good...low humidity, high barometer, and very cool temperatures (65 in dyno cell). After rejetting the carb to 40 primary metering rods/72 jets/DA secondary rods on an 'I' hanger (same total timing at 42 degrees), employing the 'big' dyno room dumps for the headpipes, and installing the air cleaner base, the max hp jumped to 371.4 hp @ 5000 rpm/459.2 lbft @ 3600 rpm (362.0 hp/447.6 lbft uncorrected) on the final pull (#14). The highest torque reading was on pull #13 at 460.3 lbft.

This engine surprised us by exceeding our first 350 hp/450 lbft prediction. It should move that heavy '78 TA with some authority."

It's installed back in the 3800 lb. Trans Am and it flat out hauls with 3.42 gears.

Dennis