I am looking at the Tubular Automotive 2" headers for the Boss 302. My question is what would the original Boss 302 heads be considered, 2v or 4v heads? Or is the exhaust port on a Boss 302 head a 2v type or 4v Cleveland type? thanks! ( I hope that question makes sense...)
You can get with Tubular and have a set made with smaller tubes and 2v flanges if you are using 2v heads. In my dealings with them, they seem to be plenty willing to help. They are a small shop, so little things are not a big issue to get done. Dave
Didn't the Boos 302 heads use the same exhaust bolt pattern as the rest of the FSB exhausts? They didn't use the offset bolt pattern the the Cleveland heads use.
I don't know about the "Boos 302"... j/k The Boss 302 was a 302 with 4v Cleveland heads. Of course it was beefed up and such, but that is the simplest discription of the engine. Therefore, it did use the Cleveland bolt pattern. Dave
The Bolt pattern is the same between the 351 C, 351 W, 302, 289, 260 and 221. All of the heads will bolt up to any of the engines if you use the right bolts and ream the bolt holes for the larger 1/2 inch bolts. The cleveland heads did not have water passages that went through the intake - The Boss 302 heads had those water passages - the Boss 302 had canted valves like the cleveland heads but they were not from or off of a cleveland engine. If you try to bolt a set of Boss 302 heads to a cleveland block you will have to drill holes in the deck tops for water flow through the heads and you would have to make or have made an intake manifold to handle the crossover flow between the heads. Very similar to the mods that have to be done when using Cleveland heads on the "Windsor" blocks. When using a cleveland head on the 302 you have to bore holes in the head for water and use a special (it is made - at least for the 351W) intake manifold and crossover. I repeat - the Boss 302 is NOT a cleveland head - IT DOES USE THE CLEVELAND STYLE CANTED VALVES. It is a "bolt on" swap for the small blocks - as long as you use the Boss pistons, rods and crank. One final note: the Boss 302 head was made from 1969 to 1970 and the Cleveland engines were made from 1971 to 1973. The Boss 302 head is not a cleveland head - it is a canted valve head like the Cleveland engines used but even the angles of the valves are different between the two of them. Did I mention that the boss 302 heads aren't Cleveland heads? That they were made to bolt on to a stock 302 block with water cross-over between the heads which is a totally different design than the Cleveland heads? Did I mention that the valve angles are different between the two heads and that the Boss heads were made two years before the Cleveland engines were made? I was sure I did.
Boss 302 heads ARE Cleveland heads. No difference in valve angles, I have no idea who told you that... No difference in bolt holes. No differences except: *The first Boss 302 heads (69) used 2.24 intake valves. Clevelands were going this route also, but they realized that this valve was too big. Even for the Trans Am series... *The water passage was moved from the block face to the intake face. Easy change... (Lucky for the Boss 302 team) *Only the 71 Boss 351 and 72 HO 351 came with the adjustable valvetrain. Same valvetrain as the Boss 302. Everything else got the non-adj... You see, in 68 Ford was working on two totally separate projects... The Trans Am racing series 302 (Boss 302 project) AND the 351c project. The tunnel port 'Windsor' style heads that the Trans Am project were using were a complete flop. They were desperate for an alternative head for the Boss 302 when it was apparent they were sitting on a loser. Ford had been on a mission to win the Trans Am series that was quickly dominated by the new Camaro. They got the engineers together that were working on each project and found that the simple move of the water passage was all it took to replace the weak tunnel-port heads. The Cleveland engineers were given some rules to apply to the new engine, one of which was that it had to use the same head bolt layout and bore spacing as the other new wave engines of that time: 289-302-351w. This was a VERY fortunate coincidence for the Boss 302 developers and saved their @sses when their head design flopped. The rest is history... Ford whooped butt at the TA series, in 70, after they realized the early Cleveland layout was too radical for the cubes. This benefited the Cleveland team and they dropped the valve size. They had time to learn because the Cleveland didn't go into production until the next year, 70 model run. Boss 302 engines were produced from 69-71 (none got into cars in 71, but they did the production run for 2 reasons: The Trans Am series rules changed after the run had started, allowing Ford to use the larger 351, which was then dubbed Boss 351 at the last minute. Secondly, Ford was having serious durability issues with the 69-70 Boss 302 engines and found themselves replacing many under warranty. The big problem was piston skirts collapsing. 351 Clevelands were put into production model years 70-74. In 74 there was such a log jam of 351 CJs that they tossed them 'willie nilly' into Torinos and Mercurys left and right. Not just the sporty ones either, but grocery getters as well. The new Mustang 2 not being available with a V8 left them in this position of overstocked engines. Did I mention that the valve angles are the same????? Cuz they are! For being so 'up' on Boss 302s, I can't see how you would have thought they had regular 302 exhaust ports...
Holy cow! I can't believe I missed this... All you have to do to put B302 heads on a Cleveland block is: Drill the coolant holes on the intake face of the head round. Install a freeze plug into each of those round holes. Drill a 7/8" hole in the block face of the head to correspond to the Cleveland block water passages. Piece of cake. No other mods... No special super-duper custom one-off intake or anything else. Attached is a pic of the original Boss 302 head, before they borrowed the Cleveland head design.
The original Boss heads were 4V exhaust bolt patterns. They were not in-line like the rest of the windsor style heads. The 2V cleveland and M head exhaust manifold bolts are a little narrower. The 4V patter allows use of big tube headers....I think you can get them up to 2 1/4" primaries...they will physically fit, IIRC. 2V exhaust pattern being different won't allow such a large primary tube and windsor heads won't allow anything larger than 1 3/4", and even then, the tubes have to be pinched a little to allow clearance for the bolts. Experience speaking of course. A lil' background on the cleveland heads: '69 Boss 302 had big valves, later ones has smaller valves. There were also open chamber 4V cleveland heads, which utilize a similar open chamber as the 2V counterparts...but with those huge ports that will flow a metric ton of air. The M heads were different...some of the later ones had the water crossover in the manifold like a Windsor style engine. I think they were '75 and later though. The M heads (later ones) are not identical to the C heads...they used thinner castings that were crack prone (well...moreso than the 2V cleveland and 4V clevelands) and there is absolutely no room for porting. Even putting in larger valves can be tough without going to hard seats because many times they'll hit water while roughing in the intake seat. Then the M heads also had probs with the exhaust valve sinking into the head which as time goes on, holds the valve open, then burns the valve and/or seat. I can't count how many M heads I've seen cracked between the valves. Even some 2V heads were like that. 2V cleveland, later 4V clevelands, and M engines all head 74-78cc chambers. Only the Boss and early 4V clevelands (as well as the Aussie 2V 302C) had the tight 55cc (IIRC) chambers which were good for higher compression. Adding dome pistons to open chamber heads was a waste because #1 the dome had to be clearanced and #2 the chambers SUCK and are prone to detonation...unless you run alcohol or race fuel. Not likely in a daily driver. M heads also have a BIG smog bump in the exhaust ports. And, to put an end to the arguing, the only TRUE Boss 302s were in '69-'70 Mustangs and are fairly rare. If you find one in a junkyard you had better gather it all up. If it was build prior to late 1968 or later than mid 1970, it was a regular windsor-style 302 with the horrible inline valve heads.
Ratio411, The head that you show in your picture is not a Boss head. It is an extremely rare "Tunnel Port" head that was never released for any street engine. It was a failure on the track because of the turbulence around the pushrod tubes that ran through the ports. The Boss heads did not have those tubes running through the ports. The 351 Cleveland intake manifold has no water passage between the heads and the Boss 302 heads do have the passagethrough the intake - you could put a stock 2bbl intake on an engine with Boss 302 heads - if you put the heads on a Cleveland you would have to make a manifold to fit and handle the water flow between the heads because the manifold that fits the Cleveland has no provision for it and it is too wide for the 302 manifold and too narrow for the 351 Windsor manifold.
