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Originally Posted by 72 mach1351  I have a 72 mach1 with the origional 351 cleveland, it is a stock 2v engine with a small cam and 500 holley with headers. stock auto with 3.70 posi rear. In its current state, it runs 9.04 in the 1/8th (best time) 8.97. Anyway, i'm building another 351 and am using closed chamber 4v heads, torker intake, 750 holley, roller cam (3,000-7,000 rpm range) same gear, 3,500 converter, 1 3/4 headers & 3" two chamber flowmasters. Any power or et guesses? Any advise on this build will be appreciated. |
From my past experience you will have far too much port volume for that combination. With the right cam (you may have picked a good one) and vacuum secondary carb it won't lay down and die at 3500, but I think you could do a great deal better off the line with 2bbl heads.
To start to show an advantage with the 4bbl heads on 351 cubes you'd have to spin the motor up over 6500 RPM. You will just be getting up where the heads are working when you run out of cam.
If you had a 4 speed you could put a big solid tappet or roller cam and a tall gear and use those heads, but I think you are in for a disappointment with a 3500 stall converter, 3.70 gear, and everything in the induction system including the intake and carb pushing towards high end.
I would ask other people who have used a similar combo, but I had no luck at all with a 4 speed using a similar combo unless I kept the engine spinning over 5000. I never tried port plates, they weren't invented yet, but I had a huge Crane roller cam and the engine kept wanting a more and more aggressive ramp so that probably meant the port flow rate was very low.
Tom
Any horsepower or ET guess? 
do to the huge intake ports on the 4bbl heads, the 4v heads are the way to go just install (PORT PLATES) on the 4v heads, Google the Port Plates, they are still sold new and make a huge diffrence in HP and torque 
