Some may remember our YouTube 496/650 dyno/drag test we did years back, the drag test was done at 5000 DA in the worst humidity I can remember, needless to say it was a horrible performance that's has bothered me ever since. So I had a customer that bought one of these 650 HP 496s and it developed a leak, didn't leak on the dyno but leaked in his car, before I moved from Colorado to Texas he brought the engine to me so we could replace the rear main seal, I was skeptical this would fix the problem but we tried, so I replaced the seal and the customer had no time for a dyno test as he wanted to get back over the border before a shut down. So he installed the engine and it leaked again, well he wanted to send the engine to me to be fixed, and he also wanted me to run the engine in my car to see if the leak was fixed. Sounds like a lot of work, but we had to do it, and I figured I wanted to retest the 650 HP 496 anyway so we went ahead. We tore the engine down and checked everything, and found nothing, so I replaced the block and put all his internals in the new block. So here are the specs on the 650 HP 496:
4.310 X 4.250
18 cc dome piston 9.8-10.0 compression
RPM 4340 center counter weighted crank (heavy)
6.385 Scat I beam rods
Isky 238/248/.578/.608/110 hyd roller
Morel short travel lifters, Straub will like that!
Scorpion rocker arms 1.7
Milodon pan with modifications
M77 oil pump
781 GM oval port heads with 1.880/2.190 valves
Performer RPM air gap intake
So we installed the engine in my car, I immediately noticed the engine felt way different in the car than they did in Colorado, a good way to put it is more harsh. We get to the local track and make a mild ck out pass, 6.85, 1/8 mile drag strip. On the second pass my is to launch the car, and I was nervous because I know what can happen, sure enough its going for the rear bumper and I try and peddle it out of the wheelie for the 60 foot clocks, the time slip reads:
1.32 60 foot
6.42 660
105xx MPH
So I'am thinking we need to adjust the front shocks, and after the shock adjustment the car will not hook, so we decide to drive the car out roll into it and tune for MPH, which turns out was a good idea, so we made several passes like that and the best was 6.40 @ 107xx MPH with 1.48-1.49 60 foots, DA was the best of 1500.
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4.310 X 4.250
18 cc dome piston 9.8-10.0 compression
RPM 4340 center counter weighted crank (heavy)
6.385 Scat I beam rods
Isky 238/248/.578/.608/110 hyd roller
Morel short travel lifters, Straub will like that!
Scorpion rocker arms 1.7
Milodon pan with modifications
M77 oil pump
781 GM oval port heads with 1.880/2.190 valves
Performer RPM air gap intake
So we installed the engine in my car, I immediately noticed the engine felt way different in the car than they did in Colorado, a good way to put it is more harsh. We get to the local track and make a mild ck out pass, 6.85, 1/8 mile drag strip. On the second pass my is to launch the car, and I was nervous because I know what can happen, sure enough its going for the rear bumper and I try and peddle it out of the wheelie for the 60 foot clocks, the time slip reads:
1.32 60 foot
6.42 660
105xx MPH
So I'am thinking we need to adjust the front shocks, and after the shock adjustment the car will not hook, so we decide to drive the car out roll into it and tune for MPH, which turns out was a good idea, so we made several passes like that and the best was 6.40 @ 107xx MPH with 1.48-1.49 60 foots, DA was the best of 1500.
