old 302 blocks

spdtrip · Jan 23, 2011

I have been thinking of building a 347 stroker, but hearing that my 95 cobra block is rated for around 500 hp makes me want to look into a stronger
block. then I look at the stronger bloocks and see the price, "GULP". I was on c-list and saw a 68 block and wondered if that was stronger than mine,
and do all modern parts ie.. roller cam, my Trick flow heads and intake, and so on work on an old block. that may be a dumb ? but oh well had to ask it.

Thanks, Mark.

Win · Jan 23, 2011

Your going to be Spending about 5-8 grand respectively for a nice 347. If i am going to be spending that much i am def going to spend the money and get a FORGED block. Your going to spend a good bit of money getting the Roller Conversion also. I would just save the money and get a Forged Block.

Sure many people have done a 347 but some like myself will say do it right the first time. I just know as stated above. Spending that much i am going to do it all out.

rz5.0 · Jan 23, 2011

stay with your block why would you need more than 500 anyways.

red94gt5.0 · Jan 23, 2011

good point above, but to answer your question, i do know the older 351 blocks were indeed stronger due to having a higher nickel content in the block, can't see why ford would have done the 302's any different in that time frame...

Pure84GTT · Jan 23, 2011

an older 302 block is going to set up for a flat tappet cam, so you will have to get a retrofit cam and lifters, and drill and tap the valley for the spider tray. the steam ports are also in a different location, and the water jacket doesn't protrude into the head bolt boss. all blocks forged in that time period have a higher nickel content, however I dont think it is quite enough to justify swapping blocks if yours is use-able . I have friends that have split mexican blocks and friends that have had late model roller blocks hold together with the same power. if you wanna spend some money on insurance a probe main girdle and a valley brace might be an option to explore.

beuchaw94gt · Jan 23, 2011

I would just go with a 351 block, should be more than strong enough to handle whats your plans are.

modo · Jan 23, 2011

blocks are not "forged"

68 block is stronger then a late model block

girdles are pointless as the block cracks in the lifter valley or from the front main to the cam bearing. when the last last time you heard of a crankshaft falling out of a sbf? if the rpms are below 6200 and there is no detonation a stock late model block will live happily past 500 rwhp.

Pure84GTT · Jan 23, 2011

the process used to cast a block is called forging that is what I was referring to

Im running a valley girdle and a probe main girdle. does it help ? who knows, but I assure you its not worth it to waste time changing block and making an old school one work.

Pure84GTT · Jan 23, 2011

this is the last 69 302 I did, it ended up lasting a few months. it had world sr's and a old school motorsport A312 cam, had the big shot plate on her with 92/92 jets buzzin her to 6700. ended up spliting hardcore..

speaking from experience, all the oem 8.2 deck blocks will break just the same

spdtrip · Jan 23, 2011

Thanks for all the input guys. So basicaly stay with my block and keep it 500 or under or spend the extra $ and go with
a good aftermarket block. BTW, when "they" say 500hp is that @ the wheels or motor? I would think motor but thought
I'd ask?.

rz5.0 · Jan 23, 2011

wheels

modo · Jan 23, 2011

Pure84GTT said:
this is the last 69 302 I did, it ended up lasting a few months. it had world sr's and a old school motorsport A312 cam, had the big shot plate on her with 92/92 jets buzzin her to 6700. ended up spliting hardcore..

speaking from experience, all the oem 8.2 deck blocks will break just the same

you were spinning it to 6700 what did you think was going to happen. i have had stock 302 blocks go 130 mph in the quarter mile with 150,000 miles on them and last almost 10 years making a tad under 600 rwhp. do you think A4 blocks were available in the early 90s when people were taking pro 5.0 cars into the low 9s / high 8s? nope.

rpm and detonation break blocks on factory stuff. sub par machining on rebuilds will also speed up the process