I'm looking for info on Zora's grand sport project race car's 377.I read a little about it in a book.Said it had aluminum heads and dual plugs per cylinder.Anyone have more info on this.I was wondering what bore/stroke it had.What platform they used seing as to how the only had 327 in 62.What about hp numbers?
Thanks guys.

 

I don't know the numbers, but I believe Smokey Yunick was instrumental in the development. Might want to check out some of his books.

 

The twin plug heads and associated custom fuel injection system never made it out of the dyno cell before the full program for 125 Grand Sports for FIA GT homologation was shut down by management, and I don't think Yunick had anything to do with the development. It was strictly a Chevrolet effort with Duntov as the supervising engineer. There is a picture of the twin plug hemi-head engine on the dyno in Ludvisgen's book. Duntov had considerable experience with hemis going back to his Ardun conversion for the Ford flathead V8 that he designed and manufactured in the early fifties before he went to work for GM. Designing and building a set of hemi heads for an existing block was right down Duntov's alley. He'd "been there, done that", but this time he had the resources of GM behind him - at least until management shut the program down.

A 377 is a standard 4" bore with a 3.75" stroke. A .030" overbore gets you to today's common 383.

The aluminum blocks were basically 327 design, but they must have had some additional internal machining or casting pattern changes to clear the crank throws. I've never been able to find any detail data on the cranktrain like journal sizes or rod and piston detail. The internal parts to make a 377/383 back then were not off-the-shelf like today.

The version of the 377 that showed up in the Grand Sports at Nassau in December, 1963 had production architecture aluminum heads with a quartet of 58 mm side draft Weber twin-choke carbs, which were (and are, today) very rare pieces as few were made. These cars were strictly done "under the table" by Duntov after GM's official reiteration of their support for the AMA racing ban in early '63, and management finally ordered that the Grand Sports be destroyed.

Duntov somehow avoided this and got three of them into the hands of the Mecom Racing Team and those were the Nassau coupes - chassis numbers 3, 4, and 5, which were heavily reworked from their original flareless fender configuration, and the aluminum 377 was also new and never seen publically before.

Chassis #1 and #2 were hidden away after they were converted to roadsters and disappeared for nearly three years. They were finally placed into the hands of Roger Penske and George Wintersteen in 1966. The Penske car, driven by Dick Guldstrand, was raced at Sebring '66 with a development L-88, and Guldstand blew off the Ford and other prototypes from the start to lead the first lap, but he was eventually forced off course by a backmarker, which damaged the suspension for a DNF.

I think the claimed horsepower for Nassau 377 was about 450. The twin-plug hemi 377 was reputed to be capable of 550.

Duke

 

Kinda neat the idea of using the 3.75 in stroke crank for a 377/383ci has been around for that long

 

You can also achieve 377 c.i. by boring a 400 .030 over and install a 350 crank. Both have certain advantages in terms of torque and HP curves.

 

Thanks for the info.I like the idea of a 377.I was curious about that particular setup froma historical stand point.

 

377 vs 383 debate has been well tested and documented by one of the hot rodding mags. The conclusion was that the heads cam and intake combo didn't care what bore/stroke ratio motor they were on, the results were almost identical.

4.125 bores had yet to be introduced back then. Come to think of it, neither were 350s. But if the block was a custom aluminum unit, then why not a big bore? SWCduke is generally the authority on this kind of stuff though.

 

I was talking with a young friend about this motor.He give me the whole 377 so what look.Then I told him this was before the 350 came out.

 

The aluminum 377 GS block had iron liners, and the designers wanted to maintain cylinder wall thickness, so they didn't go for more than a 4" bore. The first attempt to increase SB bore beyond 4" for a production engine - the 400 CID SB with siamezed bores (no water passages between the cylinders) - was not considered to be particularly successful, and it's generally not considered a good base for a high specific output engine.

The new LS7 is 4.125" bore on the same bore 4.4" bore center, so it's taken about 35 years to increase SB bore size again, but being as how GMPD has about five years experience with this bore size in the C5R engine, I figure they've got a good and proven design.

Racing DOES improve the breed!

Duke

 

A little off topic here, but I seem to recall an ad in a late 50s early 60s HotRod magazine for an engine kit for a 283 offering a 4.00" bore and a 4.00" stroke... ...might have been from Hank the Crank? Is anyone familiar with these?

 

what books ???? i have Smokey's

 

402 , I hear of people doing 408s based on 350s sometimes. 4.00 cranks need serious clearancing from what I hear. For powerful street motors my opinion is that you should always go for as much stroke your bank and your block can handle. Long rods be damned, they'll never make more power and torque than an identical motor with shorter rods and more cubes.

 

Since it was so long ago I don't remember the exact specs, but TRACO was building 377's back in the late 60's. You might give them a call and see if they have any info. They were based on 327 blocks and ran really well. A friend of mine had one in a 64 Coupe that was Grand Sported, and weight reduced, that turned a 10.9x on the old Firestone Indy tires. But, it was running one of the Camaro x-ram dual 4-bbl intakes, headers, etc.

 

Traco is long gone!

Duke