Mark Workman wrote:I don't remember hearing any power numbers, but one of the wilder modifications I saw years ago was to section a pair of Boss 302/351 Cleveland heads to fit on the 300 block. I think maybe the late Kay Sissell pioneered this(?). The one example I saw at the track had a very large amount of silicone visible at the joint, but I bet it would be a much easier thing to do today, with the aluminum heads that are out there.
Somewhat over 30 years ago, a friend of mine, the late Larry Starkey, built a bunch of them for local stock car racers. Biggest problem he had with them was...at high RPM, 7000+, the helical timing gears would break the thrust plate. He solved the problem by having straight cut timing gear sets made up. They were noisy but...if you heard one coming out of the 4th turn...you KNEW it was a Starkey motor.
Some people can break a cannon ball, in a sand box, with their bare hands
I have no clue, but I would think every about 14.7 pounds of boost would make about 190 to 195 percent above natural aspirated.
In other words, you making 100hp with no boost, add 14.7 pounds and you should make about 190 to 195hp boosted. I would think this would account for any extra friction and crap OR it would effectively DOUBLE your hp.
How far off am I? You guys that really know this stuff..
pdq67 wrote:I have no clue, but I would think every about 14.7 pounds of boost would make about 190 to 195 percent above natural aspirated.
In other words, you making 100hp with no boost, add 14.7 pounds and you should make about 190 to 195hp boosted. I would think this would account for any extra friction and crap OR it would effectively DOUBLE your hp.
How far off am I? You guys that really know this stuff..
pdq67
"It depends". It largely depends on how the boost is generated. In most cases adding 1 atm of boost pressure will not double hp as it takes power to generate the boost and the air is hotter so it is less than twice as dense as it would be naturally aspirated. But there are cases where adding 1 atm of boost can produce more than double the NA power. This is what comes from a very well thought out and built system.
LOL, according to the post count I'm an "expert." The only thing I'm an expert at is asking questions.
This is what comes from a very well thought out and built system.
It also helps to understand measured manifold boost pressure is the work done by the engine and not able to be used for moving air. The best turbocharged engines can make a lot of horsepower at relatively low manifold pressures, because they breathe so well. Think some of the Indy engines. The worst have high boost pressures and relatively low increases in horsepower; think flatheads or overheads with small valves and poor manifolding. Some of the worst ever were back in the day of the turbocharged Corvair and the Falcon I6 with the aftermarket Paxton. After a point, more boost raised the temps so much it caused detonation.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
I've built a lot of those engines, mostly for UPS- propane etc but some turbos on propane
a couple of things with the stock head- it traps air- get all the air out of the pockets or they crack
as with any Ford or Mopar take advantage of the bigger lifter- we had some custom Potvin/ Moon/ Bill Jenks grinds
the block is not near as strong as the AMC
wyrmrider wrote:I've built a lot of those engines, mostly for UPS- propane etc but some turbos on propane
a couple of things with the stock head- it traps air- get all the air out of the pockets or they crack
as with any Ford or Mopar take advantage of the bigger lifter- we had some custom Potvin/ Moon/ Bill Jenks grinds the block is not near as strong as the AMC
Isn't an AMC block actually a "smaller" big block at 4.75" bore spacing? Therefore I would think it would be stronger.
Probably not quite as strong as BBC and Ford 385 blocks..
True, the AMC does have the filled in webs while the ford block does not-however I haven't seen any issues yet with the ford block at 700HP. Bout the worst problem yet for me has been camshaft support-there aren't enough bearings to suit me and it's flexing pretty badly.
I'm working on a method for dogbone hydraulic roller lifters too...just not quite there yet.
I ran a 310 inch Ford 6 with a Sissell head & cam , Holman Moody intake and a 600 Holley in a 51 Anglia back in the early 70s. I never could keep the flywheels on it but that was before modern harmonic balancers. Tried everything with no luck, loktite, safety wire, even tack welding the bolt heads. I get about 4-5 runs then they would be loose. The motor and clutch assy were balanced together too. Just curious what you guys do today or if it's still a problem. Dont mean to hijack the original post so disregard if it's a problem.
will be interesting to see what you come up with on the lifters
but then more spring pressure and more flex or less?
not knocking the FORD-or the 292 chevy- both can be built well
but we did get 1200 hp out of a 210 inch AMC and was good for 1000 hp for 500 miles
wish we had the 4.0 block and heads
but the last several blocks had the "Mexican" OD Cores (very similar to 3 7/8 "4.0" cores with the 3 3/4 US Bore and core shaved for a thick deck- bottom end was stock though- just steel straps and head bolts for the mains
problem with flywheel bolts is they are so short and stiff that any relaxation is instant unclamping
wwmtlineman wrote:I ran a 310 inch Ford 6 with a Sissell head & cam , Holman Moody intake and a 600 Holley in a 51 Anglia back in the early 70s. I never could keep the flywheels on it but that was before modern harmonic balancers. Tried everything with no luck, loktite, safety wire, even tack welding the bolt heads. I get about 4-5 runs then they would be loose. The motor and clutch assy were balanced together too. Just curious what you guys do today or if it's still a problem. Dont mean to hijack the original post so disregard if it's a problem.
I'm not familiar with I-6 Ford, but on Chevy 250 adding two down pins (totaling three) to the crank/flywheel joint addressed that for me (in multiple engines).
Mark Workman wrote:I don't remember hearing any power numbers, but one of the wilder modifications I saw years ago was to section a pair of Boss 302/351 Cleveland heads to fit on the 300 block. I think maybe the late Kay Sissell pioneered this(?). The one example I saw at the track had a very large amount of silicone visible at the joint, but I bet it would be a much easier thing to do today, with the aluminum heads that are out there.
Quite possibly that was Bruce Sizemore's I/G Pinto, running NHRA Modified Eliminator nearly 40 years ago. For a while, he had it painted real similar to Bob Glidden's car. They cut and furnace brazed 351 Cleveland 4V heads for that. It may have even had an exhaust port plate at one point. That was a long time ago, I remember seeing it in the pits and on the track.
