how stong are the 289 blocks?
ive heard there very strong... it would not be stroked, but blown... with a main girdle and a valley girdle or something? goes in the lifter valley ive heard really strengthens it? how strong are the boss 302 rods?

 

How much boost/hp are you planning? I'm sure CPR will chime in with a more educated answer, but I bet you could build a reliable 450hp 289 block with a lifter valley girdle and maybe a stud girdle.

That said, the one big advantage a 289 has against other engines is a willingness to wind up. A supercharger isn't usually conducive to a high winding engine build. If I were to put a blower on a 289, I'd stroke it to 331 first to gain more bottom end.

 

i dont really want to stroke it, dont completely know why... haha probably for nostalgia or something..
i was planing on using gt-40p heads, lightly ported. dished pistons, all balanced.. i was hoping for around 475hp with the blower, not sure what kinda boost i could push through the stock block. it would be the weiand 174 roots

 

anyone?

 

There is no magic number a block will take.My buddy just split his making 424RWHP and another split his at 485, but another guy has one making 520 at the flywheel and its still going.Mineis at 404(probably more) but CAN make a lot more. Its just a matter of time more then power.The girdle and valley girdle(a joke) only keep the rotating assmebly together and reduce the amount of damage if you catch it in time.

 

build the crap outta it and see what happens

 

hmm, well. i was thinking of doing this, and if i split the block ill go with a world block, and 372(or however big it will go with the weiand)

289 block with girdles
stock crank
eagle rods
some kind of forged dished piston
lightly ported gt40p heads
custom cam from jay at camshaft innovations
and a pro street weiand 174 roots
all balanced rotating assy

seem good?

 

I see one problem with your goal, the lightly ported GT40 heads. If you want a supercharger to be effective, it has to breath, otherwise you are wasting your money on the Weiand. You want at least 185cc heads like the AFRs or TFS heads that will flow like the 185 AFRs. Also, bigger is not better when it comes to heads, keep that in mind.

 

hmm.. this is true.. what about some canfield 195's? with matching cam? the heads are 1350 pair assembled ive heard very good things about them.

 

I just rebuilt my 67 289. Thought about putting is a 331 stroker kit with eagle crank and rods. My machinist talked me out of it. Wound up keeping my stock crank just needed to be polished0 and refurbished my stock rods with arp bolts. ARP bolts in the mains as well. My machinest said that the stock rods and crank with the arp bolts would easily handle 450 HP with no issues. Running just under 10 to 1 compression. He advised that the 331 wasn't worth the expense for my intended use of the motor. I am opnly shooting for about 300 HP now, but may add some aftermarket heads in the future and was concerned about future upgrades. Also asked about a super charger and he also indicated ok with reasonable amount of boost. He said not to worry. I trust him, so I am not worried.