1974 455 short block rebuilt to factory spec, no bore just a hone, stock crank non-nodular, with lo-comp- pistons and no other parts,or 1969 455 long block, needs honing only with hi-comp pistons and nodular crank with G-heads. The long block is dismantled and the block has been clean and flux and the heads needs freshening the crank just needs polishing(being that long block parts are from low milage motors) olds parts dealer whom saves the better stuff and scraps the rest.Both are the same price thanks by the way this is for a 70 cutlass supreme.

 

The 69 long block, jmo.

 

Thanks any specific reasons?

 

X2 on the 69 - better foundation to start with, more HP, torque and reliability from the get go, spending close to the same!

 

Should be fine either way. The 74 will be more pump gas friendly and if it's just a cruiser it will be nice to filler up on cheaper gas. The 69 would have more torque as is. What are your plans for the car?

 

Foundation is the same, pistons are different.
You did not say which pistons the 69 engine has, low or high compression.
I ran 10.25 in a 455 years back.
You have to be able to fuel it.

Make it 9-9.5 max, with iron heads.
I'd probably go with the 74, with fresh big valve heads cut .030", for me.
I am actually going with a SBO in mine.
Gas is only going to go up in price.
My Opinion
Jim

 

The 69 in stock gear with the 4 bbl carb will put out about 100 ponies more, over the stock 73 455. The engine modifications to meet the new epa standards were not kind to hp.

 

If its a hobby car and you don't use it as a daily driver I would go with the 69 long block and around 9.5:1 compression and have the performance the 455 deserves. you will have to use premium gas. If its a daily driver you might consider going with the 74 and use regular gas. Your choice

 

Niether was the new way to measure advertised horsepower.
The 1970 W-30 was rated at 370 hp 500lb/ft torque
1971 W-30 was rated at 350 hp 460lb/ft torque (low compression)
1972 W-30 was rated at 300 hp 410lb/ft torque with dual exhaust as installed in chassis

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Jim