Ford Shelby GT500 Forum banner
41 - 51 of 51 Posts

·
Premium Member
Joined
·
4,317 Posts
The 1967 Shelby GT500 was the only year that had 2 offerings for the 428CI engine, one of which was the 355 BHP/420 TQ version with a single 4 BBL and the other was the 390 BHP/465 TQ version with dual 4 BBL's.
All I've ever known is one engine for the 1967 GT500, the 428PI with 2x4 carburetion rated at 355hp. No single 4V that I've ever been aware of.

Also, for decades there's been arguments that Shelby factory-installed some 427's in GT500's. We all know about the one Super Snake. But some 427 low-risers and med risers were said to have been available for special order. THAT SAID, I'm pretty sure that all of those theories have been shot-down and attributed to dealer-installations instead. The 427 low-riser that was factory-installed in the 1968 Cougar GT-E was 390hp, FWIW. But I've never seen a Ford 428, of any code or iteration, rated at 390. And I've never seen a 1967 GT500 with a single carb. Even with factory a/c, still 2x4 induction. That was the standard setup.
 

·
Registered
Joined
·
4,447 Posts
The 1967 Shelby GT500 was the only year that had 2 offerings for the 428CI engine, one of which was the 355 BHP/420 TQ version with a single 4 BBL and the other was the 390 BHP/465 TQ version with dual 4 BBL's.
^^^^^^I did not know that either, thanks.

Maybe we are talking about two different things? Sorry for the bad picture(s), but I was referring to the 428 listed in this original Shelby GT350/500 sales brochure.........

The GT500 428 specs.....



From this 1967 Shelby GT350/GT500 flyer/brochure.....




R
 

·
Registered
2009 Shelby GT500 Vista Blue/White Stripes
Joined
·
840 Posts
All I've ever known is one engine for the 1967 GT500, the 428PI with 2x4 carburetion rated at 355hp. No single 4V that I've ever been aware of.
That's what I thought and through my searches all I can find also. Maybe I was misinformed about this certain aspect.
 

·
Registered
2009 Shelby GT500 Vista Blue/White Stripes
Joined
·
840 Posts
^^^^^^I did not know that either, thanks.

Maybe we are talking about two different things? Sorry for the bad picture(s), but I was referring to the 428 listed in this original Shelby GT350/500 sales brochure.........

The GT500 428 specs.....



From this 1967 Shelby GT350/GT500 flyer/brochure.....




R
Looks like you are correct. I may have been misinformed like I also mentioned to 69bossnine.
 

·
Registered
Joined
·
4,447 Posts
Looks like you are correct. I may have been misinformed like I also mentioned to 69bossnine.
Thanks, and that is really not a big deal..........The big deal was that all of the 428 Shelby's chassis dyno'ed within a few single digit HP of each other, so it must be as Rick (69bossnine) said, the 335HP 428CJ's were underrated and/or the 355HP 428PI was not tuned properly because in most cases I would think a 355HP engine is going to show a higher RWHP on the chassis dyno than a 335HP engine, it might not be 20HP difference, but it should be more than 4-6HP as was the case with these tests in the magazine........

R
 

·
Registered
2009 Shelby GT500 Vista Blue/White Stripes
Joined
·
840 Posts
Thanks, and that is really not a big deal..........The big deal was that all of the 428 Shelby's chassis dyno'ed within a few single digit HP of each other, so it must be as Rick (69bossnine) said, the 335HP 428CJ's were underrated and/or the 355HP 428PI was not tuned properly because in most cases I would think a 355HP engine is going to show a higher RWHP on the chassis dyno than a 335HP engine, it might not be 20HP difference, but it should be more than 4-6HP as was the case with these tests in the magazine........

R
No Problem. Let's not forget that most manufacturers underrated their high HP engines do to insurance concerns and we really don't know by how much. One would think that 20 more HP would equate to more than 4-6 RWHP, but there are also other variables on the cahs like engine speed, drivetrain loss, type of trans.,gearing etc. too that could account for or affect this.
 

·
Registered
Joined
·
4,447 Posts
No Problem. Let's not forget that most manufacturers underrated their high HP engines do to insurance concerns and we really don't know by how much. One would think that 20 more HP would equate to more than 4-6 RWHP, but there are also other variables on the cahs like engine speed, drivetrain loss, type of trans.,gearing etc. too that could account for or affect this.
^^All true, but then that adds the other question back into the equation, a C6 automatic loss and the 4 speed manual loss, there was a C6 in one of those CJ Shelby's and there was still very little difference in those numbers between the three cars......IDK?...Yes a number of variables must have come into play, but they were all dyno'ed the same day on the same dyno, so that was not a contributing factor......

R
 

·
Premium Member
Ruby Red 2014
Joined
·
2,018 Posts
Not that it is that important, but there were only three 427 Mustangs built. All three were 1967 GT500's. All three fully documented and known by SAAC. One is the Super Snake. One is a car ordered by a friend of Shelby's from the Bay area to be drag raced and one sold to a customer from New York who flew out to California and drove it to his home in New York.

The drag Car was white and I think still resides in California. The New York car was Dark Moss green and now resides in a collection up here in Seattle.

All three had custom built headers. No cast Iron manifold that fits a 427 head will fit in a Mustang. Not even the cool '66 Fairlane manifold. Best exhaust manifold that will fit is a 428 CJ manifold, and it doesn't bolt up to Medium Riser heads and only bolts up to PI heads with modifications to the flange on the heads. All the other manifolds were 390GT logs.

The only way to get a 427 into a Mustang without custom made headers is to put 428 heads on it and use one of the above mentioned 428 manifolds.

Tho Dealers may have installed 427's in Shelbys, there has yet to be one single documented case where the 427 was installed prior to the first owner taking possession.

Yes, it was a super popular Day 2 upgrade, and before the forensic experts at SAAC parsed it out, it was very common to spin a yarn on how your 427 powered Shelby was put together by a dealer before the first owner took possession.

Never happened.
.
 

·
Registered
Joined
·
4,447 Posts
Not that it is that important, but there were only three 427 Mustangs built. All three were 1967 GT500's. All three fully documented and known by SAAC. One is the Super Snake. One is a car ordered by a friend of Shelby's from the Bay area to be drag raced and one sold to a customer from New York who flew out to California and drove it to his home in New York.

The drag Car was white and I think still resides in California. The New York car was Dark Moss green and now resides in a collection up here in Seattle.

All three had custom built headers. No cast Iron manifold that fits a 427 head will fit in a Mustang. Not even the cool '66 Fairlane manifold. Best exhaust manifold that will fit is a 428 CJ manifold, and it doesn't bolt up to Medium Riser heads and only bolts up to PI heads with modifications to the flange on the heads. All the other manifolds were 390GT logs.

The only way to get a 427 into a Mustang without custom made headers is to put 428 heads on it and use one of the above mentioned 428 manifolds.

Tho Dealers may have installed 427's in Shelbys, there has yet to be one single documented case where the 427 was installed prior to the first owner taking possession.

Yes, it was a super popular Day 2 upgrade, and before the forensic experts at SAAC parsed it out, it was very common to spin a yarn on how your 427 powered Shelby was put together by a dealer before the first owner took possession.

Never happened.
.
^^^^Cool stuff!

R
 

·
Premium Member
Joined
·
4,317 Posts
Not that it is that important, but there were only three 427 Mustangs built. All three were 1967 GT500's. All three fully documented and known by SAAC. One is the Super Snake. One is a car ordered by a friend of Shelby's from the Bay area to be drag raced and one sold to a customer from New York who flew out to California and drove it to his home in New York.

The drag Car was white and I think still resides in California. The New York car was Dark Moss green and now resides in a collection up here in Seattle.

All three had custom built headers. No cast Iron manifold that fits a 427 head will fit in a Mustang. Not even the cool '66 Fairlane manifold. Best exhaust manifold that will fit is a 428 CJ manifold, and it doesn't bolt up to Medium Riser heads and only bolts up to PI heads with modifications to the flange on the heads. All the other manifolds were 390GT logs.

The only way to get a 427 into a Mustang without custom made headers is to put 428 heads on it and use one of the above mentioned 428 manifolds.

Tho Dealers may have installed 427's in Shelbys, there has yet to be one single documented case where the 427 was installed prior to the first owner taking possession.

Yes, it was a super popular Day 2 upgrade, and before the forensic experts at SAAC parsed it out, it was very common to spin a yarn on how your 427 powered Shelby was put together by a dealer before the first owner took possession.

Never happened.
.
Did the Cougar GT-E have 428 heads? Same packaging concerns as Mustang up front, it only got longer/different at the back half of the car...
 

·
Premium Member
Ruby Red 2014
Joined
·
2,018 Posts
Did the Cougar GT-E have 428 heads? Same packaging concerns as Mustang up front, it only got longer/different at the back half of the car...
Yes, 428 heads. I don't think they were CJ heads tho cause they were done earlier than Tasca's team had advised Dearborn to move to the CJ head design (If I remember the story correctly). I don't remember when the GT500KR's hit the showrooms, but I think it was late in the year.

The thing is, 428 PI heads were really 390GT heads and those heads were no slouches in the performance department. They worked quite well on the 427 shortblocks.
 
  • Like
Reactions: 69bossnine
41 - 51 of 51 Posts
Top