Fordub

I am currently building a 70 Ranchero with a 351 Cleveland and have a 6-71 BDS blower to put on the motor.

I have had the heads redone but it still has the stock bottom end.
I was hoping to put the blower on the motor in the Ranchero and drive it with lower boost until I got a new motor put together. (Building another Cleveland) I was wondering how much boost is safe to run on a Stock Cleveland before I throw rods and melt pistons.
Any help is certainly welcome as I am not a Cleveland expert.

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ForDub
58 Ranchero 428 dual quad C6 convertible
70 Ranchero 351 4 speed "Blown"

atec77

maybe 4 to 6 LB
thats heavily under driven of course , you really need to measure the current compression and work out the ratio then we can help more .

Fordub

I was thinking around 6 lbs.That is what I ran in my 03 Harley truck safely.
The engine is a 2 barrel head 1970 model. I looked it up in the book and it said 9.5-1 compression. I am not certain this is true however.
I am going to get it running with a Holley and no blower to dial in every thing else first. Once I am happy with it I will toss on the 6-71 with about 30% underdrive just for shits and giggles.
I am also building a bullet proof 4 bolt main so later I can swap it over and smoke some bowties.
I had the heads done because one of the valves on the passenger side of the block stuck. I put it back together and another valve (same side) stuck.
I took it back to my machine shop and they reworked it. I put it back on and yet another valve stuck.
I am changing machine shops.

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ForDub
58 Ranchero 428 dual quad C6 convertible
70 Ranchero 351 4 speed "Blown"

TorinoSpeed

If your building another motor, wouldn't it be a good excuse to blow it up then have to drop the other one in?

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73' Q Code Gran Torino
Hurst 4 speed
351 Cleveland
9"
No A/C, Bench Seat, Crank windows, Just the way I like it.

Fordub

I would just hate to blow up a perfectly good cleveland just for sh*ts and giggles

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ForDub
58 Ranchero 428 dual quad C6 convertible
70 Ranchero 351 4 speed "Blown"

brenx

I've seen plenty semi stockers on 6lb's. You'd be safe there provided your timing and fuel is sorted.

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XB Fairmont (street car) 11.07@123.02mph.

TorinoSpeed

boost on cast parts won't hurt a motor. When you spin those stock parts to 5-6k, the rpm's kill the motor.

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73' Q Code Gran Torino
Hurst 4 speed
351 Cleveland
9"
No A/C, Bench Seat, Crank windows, Just the way I like it.

headsense

my two bits , i run a 6/71 on a 2v cast cleveland that already had near 100.000klms on it and also toploader and 3.5 gears .

All i did was go over the ignition and make sure it was spot on ( stock bosch electronic ) , changed spark plugs for two ranges colder than factory spec , run the engine on pump 98 ron ( usually Shell ) , fatten up idle mixutres ( 2x 600vac ) and she's happy as a clam 6.5lbs boost and wont drive in a straight line . Static comp at 9.2 : 1 ,fuel pressure at 5.5psi idle , check plugs after punishment and blow by through tappet covers , all good so far .

No two engines are the same but a good cooling system and keeping the revs to no more than 5800rpm seems to agree with it

headsense

forgot to mention is 351 open chamber , seems to like 4.0degrees inital timing for easy hot and cold starts and plug gaps out to max recommended .

geos sho

watch your oil at the crank, i cut bth my main and rods 20 thous. and run oil restrictions in the mains trw forged 30 over and smoothed the lifter galley opened the return port behind the distributor and added holes in the valley for oil return. just my 2 sense and i spin it @ 7000 for the last 18 years!!! no shit

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my need is speed