jeff@oblio.UUCP (Jeff Buchanan) (03/02/85)
> > My roommate and I have two (we paid only $1950 for each, and got them immediately). The problem with these motors is that they must be torn down and inspected thoroughly. They have been known to come with rod bolts missing or lying in the pan, loose mains, etc... Also, I find the term "wild cam" for LS-7 grind absurd. That's what I consider a street grind. The only unstreetable aspect of the motor is the compression. Unfortunately, Cheverolets need the compression to produce horsepower. If you've got a readily available supply of SoCal this isn't a problem. Pound for pound, I'll take Chrysler motors over Chevrolets every time (Big Block or Small Block), they don't need the compression to produce the same horsepower, and they always produce more torque (which is the dominating factor in street racing). Shelby Thornton Relational Technology > > This response is partially correct. The LS-7 is certainly a street grind, as it has 260/272 degrees duration, (intake/exhaust) @ .050" lifter lift. This is measured duration, not factory advertized. The motor is very streetable, the compression ratio is lower than most people think, nominally around 10.5-to-1 for an open chambered 427. The factory advertized 12-1 assumes a combustion chamber of 116.9 cc which the heads do not have. Also, a -.005 deck height. Heads are typically 122 and deck is about +.008. With a .040" head gasket, 10.5 is the CR. If the Chrysler engines are so great, why did you buy a rat motor? First of all, they DON'T produce the same horsepower with less compression. They DON"T produce more torque, and most of all, torque is not the dominating factor in street racing. In all forms of racing, horsepower is what counts, because horsepower = torque*RPM. As far as accelerating a car, you try to maximize torque at the rear wheels which means maximizing horsepower at the flywheel. Think about it. If you had 1000 ft. lbs. at 1 RPM, you would have to gear the car so high to get vehicle speed, you would have only a tiny bit of torque at the rear wheels. A motor that produced 500 ft. lbs. at 7000 RPM would produce much more power and do much greater acceleration. Now I'm not saying Chrysler engines aren't good, in fact you might even be correct about small blocks, although I doubt it. The rat motor is far superior to the 440 series "B" motors. Look at the basic design of the two engines. Canted valves on the rat vs in line on the Mopar. Rat ports are much bigger, and the open combustion chambers are clearly better. A 440 producing more ponies than an open chambered L-88? Dream on, friend! As far as the hemi is concerned, now that's another matter. To me, hemi's are the bad guys and rats "ride the white horse", so to speak, but I have to admit that they are a superior design. However, in all my years of street racing in various parts of the country when REAL cars ruled the streets (60's, early 70's), I never heard of a good running hemi on the street. Invariably, the 10 fastest cars would all be rat powered Camaros, Corvettes, GTOs, Novas, etc. Then came your 428 Cobra jets, hemis, 440, small block Chevys. If the Chrysler motors were so much better, how to you explain the overwhelming majority of super hot cars were Chevy powered? Jeff
shelby@rtech.ARPA (Shelby Thornton) (03/09/85)
> If the Chrysler engines are so great, why did you buy a rat motor? It was cheap horsepower for a boat. > First of all, they DON'T produce the same horsepower with less compression. Now that I think about it, you're probably right, the RAT probably does have more horsepower. > They DON"T produce more torque, and most of all, torque is not the > dominating factor in street racing. When I say torque, I mean usable torque. Rat motors don,t know what that is. I've watched my 440's destroy any and all 427s and 454s that they've run across. I know I don't have the horsepower of some of these motors, but my mid-range torque destroyed them. > Now I'm not saying Chrysler engines aren't good, in fact you might > even be correct about small blocks, although I doubt it. The rat > motor is far superior to the 440 series "B" motors. Look at the > basic design of the two engines. Canted valves on the rat vs > in line on the Mopar. Rat ports are much bigger, and the open > combustion chambers are clearly better. A 440 producing more > ponies than an open chambered L-88? Dream on, friend! Did you know that the 440 was an open-chamber motor? Probably not. Did you know that the smaller port produced a higher port velocity to increase low and mid-range torque? Porbably not. Did you know that Chevy was a 3rd class citizen in racing in the sixities (behind Chrysler and Ford)? Probably not. A factory "B" motor in the sixties was probably the best motor to hit the streets, the Chevies couldn't come close. But now Cheverolet has continued racing development for the past fifteen years, many years after Chrysler stopped. I hope todays factory Chevy equipment is superior, it has a fifteen year technology advantage. > as the hemi is concerned, now that's another matter. To me, hemi's > are the bad guys and rats "ride the white horse", so to speak, but > I have to admit that they are a superior design. However, in all my > years of street racing in various parts of the country when REAL > cars ruled the streets (60's, early 70's), I never heard of a good > running hemi on the street. Invariably, the 10 fastest cars would > all be rat powered Camaros, Corvettes, GTOs, Novas, etc. Then came > your 428 Cobra jets, hemis, 440, small block Chevys. If the Chrysler > motors were so much better, how to you explain the overwhelming majority > of super hot cars were Chevy powered? It's funny to notice what dominates Super Stock racing, what was that you said? Ah yes, the Chrysler hemi. It would be nice if you noticed the factory cames that came in Chryslers. Hemi's had .471 @ 284 degree duration (no cam). The "B"'s came with .425 @ less duration (I forget the exact number). Even Cheverolet books admit that the Chrysler motors were under cammed from the factory and that the factory horsepower ratings were ridiculously low! Today, Chevy dominates all racing but Super Stock and Fuel classes, but they should. While no one else has been developing race parts, Chevy has been going full blast. I have alot of respect for the NEW Chevy parts, but my "B" Chryslers still rule the streets. Shelby Thornton Relational Technology P.S. In defense of FORD, the 429 BOSS was probably the second best motor ever produced, but then it is a HEMI design.