can anyone tell me the differance between the two?are the blocks stamped with the vin.#?
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The heads where differant, intake manifold was differant, it had solid lifter cam, four bolt mains, selected conn rods and pistons... I think there is a website out there called what is a boss 351. It goes over all the differances one by one.
Which is considered better for performance?
I've worked on & driven mustangs with every flavor of 4V Cleveland engine in it, including the 3 variations in juice motors: '70 - '71 351C 4V, '72 351 Cobra Jet, '73 351C 4V (the egr motor); and both solid lifter motors: 351 Boss & 351 HO.
All of the motors listed above have big port heads. All but the egr motor have the big valves. Only the '70 - '71 351C 4V & Boss 351 had the closed combustion chambers to raise compression.
The '70 - '71 motor had a small 600 cfm Autolite 4300A carb. The early motor had the smallest cam too, and it was the only one of these motors to have a single point distributor or a 2 bolt main block. The early motor was the worst performer as it came from the factory.
The rest of the motors had dual point distributors, 4 bolt main blocks, 750 cfm spread bore Autolite/Motorcraft 4300D carbs.
The solid lifter motors had fordged pistons, the others were cast. The solid lifter motors also had better connecting rod bolts, shot peened connecting rods, the cranks were brinnel tested to meet a minimum hardness spec. The heads were set up for adjustable valve train. The 351 Boss had pistons with pop up domes to raise the compression, and it had a hotter camshaft, compared to the 351 HO.
Driving the cars, the 351 Boss was the biggest gas for sure. It was a very powerful package, accelerated good. About as good as the Pantera. Now imagine that motor in a Pantera!
Comparison between a 351 HO and a 351 Cobra Jet, both with 4 speed trannies, is a very close race. Hardly justifies the expense & maintenance of the solid lifter camshaft. Both good motors by the way. At the time, NO small block chevy could touch them.
The early motor, the '70 - '71 351C 4V seemed like a strong performer until the '72 Cobra Jet came along. Then it became obvious how strangled the early motor was. The Cobra Jet wanted to rev just like the solid lifter motors.
So, yeah, the 351 Boss was the high point among production Clevelands, but the '72 Cobra Jet was no slacker either, tied for second with the 351 HO. Overall I would recommend the '72 Cobra Jet for a daily driven car because of its self adjusting valve train.
I have modified the '72 motor by zero decking the block, adding the quench heads, a hotter hydraulic cam. Kept the Autolite carb, but added headers and a free flowing exhaust system. In that state of tune the motors produced between 375 to 400 bhp and felt every bit as strong as the 351 Boss. Drivability was excellent, no reliability problems either. And the cars past smog in California.
your friend on the DTBB
All of the motors listed above have big port heads. All but the egr motor have the big valves. Only the '70 - '71 351C 4V & Boss 351 had the closed combustion chambers to raise compression.
The '70 - '71 motor had a small 600 cfm Autolite 4300A carb. The early motor had the smallest cam too, and it was the only one of these motors to have a single point distributor or a 2 bolt main block. The early motor was the worst performer as it came from the factory.
The rest of the motors had dual point distributors, 4 bolt main blocks, 750 cfm spread bore Autolite/Motorcraft 4300D carbs.
The solid lifter motors had fordged pistons, the others were cast. The solid lifter motors also had better connecting rod bolts, shot peened connecting rods, the cranks were brinnel tested to meet a minimum hardness spec. The heads were set up for adjustable valve train. The 351 Boss had pistons with pop up domes to raise the compression, and it had a hotter camshaft, compared to the 351 HO.
Driving the cars, the 351 Boss was the biggest gas for sure. It was a very powerful package, accelerated good. About as good as the Pantera. Now imagine that motor in a Pantera!
Comparison between a 351 HO and a 351 Cobra Jet, both with 4 speed trannies, is a very close race. Hardly justifies the expense & maintenance of the solid lifter camshaft. Both good motors by the way. At the time, NO small block chevy could touch them.
The early motor, the '70 - '71 351C 4V seemed like a strong performer until the '72 Cobra Jet came along. Then it became obvious how strangled the early motor was. The Cobra Jet wanted to rev just like the solid lifter motors.
So, yeah, the 351 Boss was the high point among production Clevelands, but the '72 Cobra Jet was no slacker either, tied for second with the 351 HO. Overall I would recommend the '72 Cobra Jet for a daily driven car because of its self adjusting valve train.
I have modified the '72 motor by zero decking the block, adding the quench heads, a hotter hydraulic cam. Kept the Autolite carb, but added headers and a free flowing exhaust system. In that state of tune the motors produced between 375 to 400 bhp and felt every bit as strong as the 351 Boss. Drivability was excellent, no reliability problems either. And the cars past smog in California.
your friend on the DTBB
quote:Driving the cars, the 351 Boss was the biggest gas for sure. It was a very powerful package, accelerated good. About as good as the Pantera. Now imagine that motor in a Pantera!
That's the motor I have George! Plus the "Street Brute" Items from Hall Pantera.
quote:Posted May 28, 2006 04:43 PM
quote:
Driving the cars, the 351 Boss was the biggest gas for sure. It was a very powerful package, accelerated good. About as good as the Pantera. Now imagine that motor in a Pantera!
That's the motor I have George! Plus the "Street Brute" Items from Hall Pantera.Emery,pantera's didn't come with boss motors.Somone could've put one in later.That would have been a great combination, the boss 351 and the pantera.
Thanks
Emery
Jwr2968-yep I knew that. Gary hall had a Boss 351 block and built the motor for my car for the previous owner. It is fast!