SD silver diamond

i found a silver diamond motor i can get for almost free. i have a 560 im gonna start to pull.it has a 301 ci in it. will the SD head work on 301 block?. will it get better flow?. thanks

These truck motors came with 2 types of heads: straight-valve head, and a tilt-valve head. Tilt-valve head has a wider valve [rocker] cover. ALL SD's were straight-valve heads, as far as I know. EARLY Black Diamond motors also were straight valve motors, but later BD motors were tilt-valve motors. Obviously, the tilt-valve motors were considered an "improvement" over the straight-valve motors.

The straight-valve motor is still probably an improvement over the ag engines, but probably not for the reasons you might think. The truck motors were set up for a max of 3600-3800 rpm, so I wouldn't be surprised if you ran out of flow there on a stock set of ports. BUT the combustion chambers are supposedly smaller [and shaped differently] than the ag motors--not that I've CC'ed either head--and would raise your compression ratio.

On the OldIHC truck forums a couple of years back, some guy was mixing and matching parts between a straight-valve engine and a tilt-valve engine. Apparently he used pistons from a tilt-valve engine with a straight-valve block and heads...and wondered why the motor overheated and pinged. Turned out the static compression ratio ended up around 13:1, based upon the compression numbers he was getting. Not saying you'll get anything close to that...but I've heard that using the truck heads WILL raise compression over using the ag head.

thank you for all the info!!!! i think i might just get the motor. ill pull the valve cover off today and see if its a strait valve or slant valve. thanks!!

Did a BD308 and BD282 use the same rods? I picked up some BD308 rods measuring 2-1/8" jornal by 8-9/16" long center-to-center. Were there other similar rods made? I've found references to dozens of IH 6cyl gassers. 262 being one. I guess a bunch of flat head stuff too.

The truck head will fit on your 301 block, but you need to use the head bolts, valve cover, rocker arms and push rods from the truck head. The chambers is MUCH smaller. It will raise your CR at LEAST a point. The ports flow much better as well.

thanks for the info snot nosed kid. i really appreciate it. i know more about the farmall 4cyl motors.will i have to run race gas?.thanks

you can visually see the skinny valve cover. you will also see the ports exposed in the casting where the manifold bolts up. the chambers work best with flat top pistons only. firecrater r tight fit, but can be massaged to fit the domes. its supposed to boost cyl pressure by 50psi. you can port the exhaust side huge! much bigger than the tractor heads, that helps get air moving thru, which the tilt valve heads, r very small thru the exhaust ports stock. aint worth it if she has the big valve cover cause itll be the same as the tractor head if it has the big valve cover. ok well, maybe the cam being a 4000 rpm engine vs a 1900rpm engine, but, we dont know, if the truck cam grind is the same as the tractor cam grind.

what years were the strait valve motors? how bout the tilt-valve?

thinking they changed close to 47-48 to the tilt valves. ive never traced back how far the sd motors go in the trucks n dozers, the 6cyl of that whole line could date back to early 40s. seen 4, 49 model IH trucks that all had tilt valve heads on em.... gotta be pre 48 to find one.

well i took valve cover off and head today. its a strit valve SD. Now is it worth the effort putting a strait valve on my 301 block? should i port it?. thanks

How do you tell what color diamond engine you have? There is an old IH truck with a straight 6 not far from me and would like to know what it is. Thanks

The SD engine began production the same time as the L-series trucks...about November of '49, for 1950 models. The SD engines only came as the SD220 and SD240...same bore, different stroke. Only when the tilt-valve BD's came along--and IIRC, the tilt-valves weren't until '58 or '59--did IH go as big as the BD264.

The so-called BD308 and BD282 were simply variations on the old BLUE Diamond engines, and were not designed off the SD or "true" BLACK Diamond engines. The BD220, 240, and 264 became the BG221, 241, and 265 when equipped with PCV valves instead of road-draft tubes for crankcase ventilation...and ended at the end of 1968 truck production. 1969 and up IH light truck sixes were purchased from AMC.

Not sure what "tilt-valve" engines YOU'RE talking about...but it sure wasn't anything in the SD or BD line of engines. Maybe the Red Diamond engines were "tilt-valve" engines...but their parts won't interchange with an SD engine any more than the Blue Diamond engine parts will.

Engine size designation should be stamped on a machined flat on the passenger side near the front of the block, just below the head. Silver Diamonds will be marked SD220 or SD240. Black Diamond engines will be marked BD220, 240, or 264...although some Canadian BD engines were marked B220 or B240. Green Diamond engines will be marked GRD-175, 214, or 233. Blue Diamond engines will have BLD, and Red Diamond engines will have either RD or RED in the stamping.