496 crate motor?

[hotrodchev]

All this talk about big-block crate motors got me thinking about a story I was told approx. 12-15 years ago. The father (now deceased) of a close friend of mine use to tell us the story about a "496" crate motor he and his partner had purchased at a local dealership to run in their 1968 Chevelle drag car in the early to mid-1970's. He claimed, it was sold as a marine motor, so they had to change the intake and a few other components in order to set it up drag racing. Apparently, they could never get it to run right mated to an automatic, so they switched to a 4-spd. manual and it ran like a charm at high RPM. When the drag strip closed down in 1979, the car was parked and the motor was sold to a neighbor who apparently tucked it away in the corner of his garage. I don't know if the motor still exists today, but I might possibly still be able to track down this person if it's worth persuing. I recently paged through a Big-Block Chevy catalog I have and there is brief mention of a 496 Big-Block engine along with several other "rare" high performance engines. I'm very curious if anyone else has any further information about the 496's and if it's true that many of these "big" cubic inch motors were always sold over-the-counter as marine motors.

Thanks,
Tim
"HotrodchevII"

[hotrodchev]

Correction, I believe the crate motor that he was referring to was actually a 495 and not a 496. The book I have lists a 495 aluminum race block with cast iron liners, 4.440" bore, 4" stroke, 61.932" cylinder volume and 6.135"/1.53 rod length/rod ratio. The 495's are listed in the book as being built in 1970-71 and are extremely rare. There's no mention of the primary application for these motors, but being aluminum, I would guess that they probably were built for marine use.

No takers on this subject?

Thanks,
Tim
"Hotrodchev"

[jg95z28]

I was only 5 in 1970, so I can't help you on this.

[GMH454]

Without cross checking bores and strokes the date of 70-71 makes me think it is referring to the second of the special alloy Can Am blocks Chevrolet built.
Think they were 356 alloy same as ZL-1s
Specifically built for the Can Am circus, although Grumpy used a short stroke one (might have been the 390 alloy version ) in his 1970 Camaro. Later used by Group 6 Vette and Camaro racers in Imsa and T/Am.
Rare is kind of an understatement.

[hotrodchev]

[ QUOTE ]
I was only 5 in 1970, so I can't help you on this.

[/ QUOTE ] Hey Jeff, no excuses. I was only 4, so you had a whole year to be studying and soaking in this information. LOL!

Very interesting GMH454. In those years, Can/Am racing was in it's heyday up here at Donnybrooke International Raceway in Brainerd, Minnesota. Maybe it's possible that a few of these 495's made their way up here back then, but I highly doubt one could be bought over the counter by an average Joe. Last night, I was doing some more thinking about this motor that my friend's dad was telling me about and I'm now beginning to wonder if maybe it was an LS-7 motor he purchased over the counter.

Does anyone know if this is how the LS-7 crate motors were sold over the counter, for marine applications only?

Tim
"Hotrodchev"

[GMH454]

[ QUOTE ]
but I highly doubt one could be bought over the counter by an average Joe.


[/ QUOTE ]

Back in around 1972 Chevtolet released the GREEN BOOK, a parts catalogue and Hi-po manual. Both the 356 & 390 Can Am blocks are listed.
Depending on the dealer pretty sure they were over the counter, but unless you were on the discount list, they were not cheap.

[hotrodchev]

I made contact by phone with the neighbor who owned this engine last and as it turns out he still has it. He also confirmed for me that it's a mid-1970's LS-7 motor, but it's not for sale at this time. So, I did the next best thing and left him my name and number and told him to give me a call when it's time. At least for now I can consider this mystery solved.

Thanks,
Tim
"Hotrodchev"