Originally Posted by MotorHead

Engine made 425HP in 1965, 50 years later the new Straub cam made how much more ? Can't see the HP numbers in the thread.

Originally Posted by ajrothm

I haven't drove it yet... and I only drove it once with the previous engine which had a flat cam and ran terrible..

Yes this one only made 441hp but it had a few things going against it.. Questionable spark plug wires that were arcing, two rocker arms that apparently were set incorrectly by the builder during assembly..(I just reset the valves today adding preload and found two that were flopping on the valves).. Then the aforementioned 650 carb mistake vs the 780 cfm that comes on a stock one...

I am pretty confident that this one would make an honest 460hp+ now with the small issues resolved and a 780 carb with manifolds, and probably 490-500hp with 2" headers.

In regards to a stock 396/425hp engine in true oem form, first off, they were dynoed by GM with headers and no exhaust in the SAE gross rating era (to the best of my knowledge and research), where as we dynoed ours thru stock manifolds, that's an easy 30-40hp loss.. And then the factory 396 probably didn't make a TRUE 425, it was probably a bit less due to varying tolerances...(ie. pistons down in the hole like ours was).

I'm sure ours even with less compression is likely a bit quicker then a stock 396", especially once I get my custom side pipes built with 2.5" ID classic chambered pipes and true 2.5" head pipes, vs. the stock side pipes with 1 5/8" ID and crinkle bent head pipes that neck down to 2" in some spots and known to kill 50-60hp+.

I may eventually chasis dyno this one and see what it makes with some tweaks...for now I just want to finish everything and get it cruising for the spring.

Originally Posted by jb78L-82

Very cool...Good luck. Sure seems like a nice engine.

Originally Posted by ajrothm

She lives finally, after a year of being down.

Cam sounds pretty damn good in this motor if I do say so myself.. Got a little "thump" for sure... Its a Straub Tech 237/245* @ .050, .620/.566" lift, 109 LSA hyd roller.

I re-adjusted the valves today with more preload and I found 2 that were way off.. I wish had checked them myself before dynoing it, I have a feeling two cylinders may not have been 100%...

1965 Corvette 396/425hp idling - YouTube


I still have to finish dialing in the timing curve, put the ignition box back on and tie up all the wiring harness behind the distributor so excuse the mess... It will be right in a few days.

Also I have some custom 2.5" ID Classic Chambered pipes we are going to build side pipes out of so it will flow much better then the choked out 1 5/8" ID stock side pipes..

Hopefully we'll make the maiden voyage in another week or two..

I will soon start rebuilding the original 65' 780 cfm vac sec so we can put the factory fuel line, filter, PCV tubing back in...not to mention gain 130 cfm worth of flow over the tiny 650 DP that is currently on there.