two different mosters the boss block is built to handle alot more power and they came with cleveland heads with huge valves..and from what i've hered on stang forums there not very streetable engines the regular 302 can make alot of power and are way way cheaper..you can even use the new boss block my dream engine is a BOSS 375 ...new boss block punched out to 375 ...cleveland aftermarket heads ...victorjr ..retrokspeed BOSS EFI
the boss 302 has a stronger block i believe, the boss's are thicker...but i dont know much on that subect so your better off taking someone elses word over mine...
Besides the heavier block the biggest advantage was the Cleveland heads. Back in the day the 'bigger is better' theory applied to head ports and 'smaller is better' for combustion chambers. In their day these heads flowed like mad, but that was up at the highest RPM range. Today we know more about flow and keeping fuel in suspension and superior combustion chamber design. In many poeples opinion the aluminum heads of today outflow the old Cleveland technology. If you are going for the 'wow' factor, it would be neat to build a home made boss engine...but you'd have to source an intake and heads but you're still looking at 30 year old technology. Given the pricing of the offerings from AFR, Edelbrock and the rest it makes more financial sense to go with new technology. Just my 2 cents!
My uncle drove his '70 Boss 302 daily for 11 years. He got the car when he was in high school and drove it until 1989 when he bought a new '89 Mustang 5.0 hatchback.
The Boss 302 was offered in 69 and 70. It came with four bolt mains on two, three, and four caps. The crank was forged steel and the rods were huge and fitted with 3/8" bolts. The block was cast of a higher nodular cast iron and had thicker cylinder walls. The external freeze plugs were fitted with screw-in plugs.The heads had the same cooling passages as the other 289 and 302's but were fitted with canted valves like the Cleveland heads that came out in 1971. They are not the same heads. The Cleveland heads do not have the water ports to the intake and the Boss heads do. The Boss rockers were 1.73:1
You were misinformed. I had a ride in a 70 Boss and it was an awesome ride. I'll add this to what the others posted about what the Boss consisted of: The heads were basically the same as the 4bbl quench (70-71) chambered Cleveland heads, but with the coolant ports revised to work with the Windsor block. Camshaft was a solid lifter. Only thing really missing was headers. These were 8000 rpm capable engines from the factory. Intake was an aluminum dual plane high rise with a 780 Holley carb.
Baddad, If the heads were Boss 302 heads they didn't have modifications to the water passages - they were cast that way from the factory. If it was using Cleveland heads then yes, water passages would have to be added. The reason these engines have a reputation for being poor street engines is because they are configured from the factory for high rpm use and on the streetthey have almost no low end - especially if they are in a heavy car with an automatic transmission. The 780 cfm carb didn't help the low end either. Once you get the Boss 302 into it's torque curve it is a rocket. You have to drive a car with these engines in them - it is not the car to idle around town with.
I'm well aware of the differences in the Boss heads, but the fact remains that they're essentially 4 bbl Cleveland heads with revised coolant ports. The 780 wouldn't affect the bottom end either, it's a vacuum secondary carb. With the rear gearing most had, around town driving isn't a problem.
Actually, the Cleveland heads are modified Boss heads. The Boss heads were made for two years before there was a Cleveland.
My friend's Boss Mustang at the time (mid 70s) had a 3.50:1 rear gears, it wasn't very peppy below 4000 rpm, but after that, HOLD ON! 8000 + rpm shifts. The Cleavland heads were actually developed from what Ford learned from the Boss heads. HUGE ports in the Boss heads, you could drop a golf ball down the intake ports. Which is kinda rediculous for a little 302. My friend actually ended up pulling the Boss motor and crating it away and installed a 351 Cleavland with the 2v heads. That combo would run circles around the 302 Boss at any speed.
Now you're nit-picking. Being as more Clevelands had these heads and most guys aren't aware of the differences that made the Boss 302 unique unto itself, that is why I describe them as Cleveland heads. You are correct though. But if you REALLY want to get down to semantics, all the Boss 302, 351C and 429/460 canted valve heads were originally Chevy designs. The Chevy 427 engine of 1964 was the originator of the design. Ford just borrowed it and tried to improve it. They succeeded on the intake side but blew it on the exhaust. (as usual for that era, with the excption of the FE heads)
According to the history books that I have on Ford engines: HPBOOKS; says that the 351C was introduced in 1970. S.A.Design; Ford Performance says; "Too bad it (351 C) died so young (it was produced in 71, 72, and 73 only);..." Petersen; Ford High Performance says; " produced in 1970 with the 250 hp 2bbl and 300 hp 4bbl and introduced in 1971 along with a Boss and Cobra Jet version..." From Petersen's Complete Ford Book; in the history section "1970 351 250 hp 2bbl (same as in 1969) 1970 351 300 hp 4bbl (change from 1969) 1971 351W 240 hp 2bbl (down from 1969) 1971 351C 240 hp 2bbl (first "C" designation) 1971 351C 285 hp 4bbl" The first Clevelands were produced in 1970 but it is a matter of contention whether there were any put into cars until 1971. In 1969 there were two versions of the Windsor a 2bbl and a 4bbl that carried over into 1970. As far as I know the only four barrel 351's in 1970 were the carry over 4bbl Windsors and the two barrels were all Windsors. If you bought one new with a Cleveland in it then I (and the books that I have) are wrong. I have never seen one and the one person who showed me his Cleveland 4bbl turned out to be a 4bbl Windsor. Those were supposed to be 1969 only so anything is possible with father Ford at the controls. Nothing would surprise me.
Paul, there's an old lady that used to run around town here that has a 70 Stang, Mach I, and it definately has a 4 bbl Cleveland. We used to have a muffler shop and did oil changes and we did oil changes on that car several times. Both me and my brother and at least one friend of mine tried several times to get her to sell it, but she wouldn't. It was her son's car and he had passed away. It seemed a shame to us for her to putter around town with a car like that. It even had a shaker scoop on the Cleveland. I've also seen lots of 70 Torino's with Clevelands.
