whats a better build, a smogger 455 or a 1970 350?

[shaks 442 clone]

the 350 in my cutlass needs a bit of work to get it back up in running which includes a sleeve which i can do at school in our machine shop it costs about 30 or 40 bucks

and the crank needs to be either be replaced or completly gone thru to get rid of the thrust wear and the journals are grooved badly not sure if that can be welded but the teacher said it would be about $200 to get that crank back to working condition

or

should i just go buy a smogged 455 and build that up ?

[Oldsmaniac]

If you want to keep it stock the 350 is a good engine and less thirsty for the high priced fuel we have these days. A 455 will give more punch be more thirsty and will require some adapting with brackets, maybe a bigger radiator, heavier front springs, and a turbo 400 trans is recommended. Why build a smogger though? The 455 needs no more smog controls on it than your 350. The later 455's have lower compression ratios and the heads are designed for unleaded gas.....both of these aspects are good for a street engine.

[don71]

I would pick the 455 smogger or not. Basically the two engines cost about the same to repair and upgrade under most conditions.

The fuel milage with the 3 speed auto between the two, is debatable. Assuming you have a 2:56 rear (even a 3:08), the 455 is not that bad for mpg. You're looking at 12-15 with either engine in a heavy cutlass.

Besides, the 455 will put a grin on your face everyday.

[silverriff]

I have a 72 with a 455 and cherrybombs and its bada$$. Like don71 said, it puts a smile on my face every day. It does love its gas, but if I was that concerned about fuel economy, I'd drive a Cobalt. Thats not why we drive these cars. Go for the big nasty 455, you'll love it. There is nothing like starting your car up at 7 in the morning and almost rattling your neighbors windows out of their frames.

[daverbmxer]

Originally Posted by Oldsmaniac

...and the heads are designed for unleaded gas.....both of these aspects are good for a street engine.

You can run unleaded gas on a pre-smogged engine though, and it will still be streetable and run fine right?

[Oldsmaniac]

Pre 1971 heads did not have hardened exhaust valve seats and lead in the gas acted as a cushion. Some swear that the use of unleaded gas will be detrimental with the older heads. I have had no experience either way and also remember that American Premium was unleaded gas back in the 1960's and never heard of any problems from people who may have used it exclusively.

[joe_padavano]

Originally Posted by Oldsmaniac

Pre 1971 heads did not have hardened exhaust valve seats and lead in the gas acted as a cushion. Some swear that the use of unleaded gas will be detrimental with the older heads. I have had no experience either way and also remember that American Premium was unleaded gas back in the 1960's and never heard of any problems from people who may have used it exclusively.

I'll second that. I ran a set of B heads for years on unleaded with no ill effects. If this is an infrequently driven car, you'll never see the difference. If this is a daily driver that racks up 20,000 mi a year, you MIGHT need a valve job a little sooner.

[DennisG.]

I would`nt waste the time and money on sleeving that 350 block. Find another 350 or go with the 455.

[71 delta88guy]

I loved my old 455. After upgrading the ignition to msd with pertronix distributor mod and leaning out the 650 holley it had I got 17.3 mpg. GRANTED that was a test. I kept my foot out of it for a whole tank of gas just to see.This is in a 71 delta 88 convertable. Having torque to spare is a wonderful thing. This result was not in a stock 455. I had a 495 lift,230 @.050 duration, edelbrock intake,hedman headers,2 1/2 duals,th400 shift kit,2500 stall converter,e heads worked a bit. A nicely thought out combinatioin. So build the big block,use parts well matched,don't buy new stuff,use e bay,save money,and remember machine shops are there to suck the money from your wallett.

[Omicron]

Definitely go with the 455. Once you go big block you'll never look back.

[Run to Rund]

It will cost the same to build either engine, maybe less for the 455 since you could find a good one that doesn't need crank etc. work. Once worn, the thrust surfaces would need to be built up, iffy with any crank, espeically a cast crank. If you are getting another core engine, which would be by far the best, either 350 or 455 will cost about the same. The fun factor will be much greater with those extra 105 cubes.

[marzgtp1]

I'd go for the 455 lots of torque. I love it I just changed the heads on my 70 cutlass w /a 72 455

[shaks 442 clone]

Originally Posted by marzgtp1

I'd go for the 455 lots of torque. I love it I just changed the heads on my 70 cutlass w /a 72 455

???

explain.

[88 coupe]

Originally Posted by shaks 442 clone

........ a sleeve which i can do at school in our machine shop ........

Hard to put a price on the learning experience.

Norm