Thread: 427 or Twin-turbo 283 power?

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I need opinions for powering my 66 Chevy II project in the near future:
One is: I´ve got the original 283 block, it's in mint condition, and i planned on boring it .060, using Vortec heads and installing twin turbos, or...
Two: I also have a 454 block, in really good shape, and in that case will use a steel 427 crank (like the revs) and 781 or 049 oval port heads.
The car has a Heidt´s front end and a reinforced frame, i´ll also reinstall the original M-20 trans (once i rebuild it), and will use a rather long rear ratio (3.08 3.23) because the car will be almost always street driven, and since gas here is kinda expensive i want to have some decent mileage, besides the frame is really light so my guess is i´ll still be pretty quick
I really like both of them because the rat will have lot's of torque, but the turbo powered 283 will hang in there in my opinion, and get better mileage also, any thoughts????
The mechanical aspect is not an issue since i really enjoy wrenching!!
Thanks
Martín

what about a 427 twin turbo?????? either way gas should not be the issue, they both will suck it down , however i think the little 283 with the turbos will be better on gas mileage. but there is nothing like the sound that , that big block will produce ,

there is no substitute for cubic inches.

Originally posted by junior
what about a 427 twin turbo?????? either way gas should not be the issue, they both will suck it down , however i think the little 283 with the turbos will be better on gas mileage. but there is nothing like the sound that , that big block will produce ,

there is no substitute for cubic inches.

junior, ya' beat me to it. BB TT.

I would go with the 427 cranked 454, bored 30 over, with a set of square port power ported heads.
The 283 you have there is a Duntov motor if it's orignal, and if it's complete it's worth a mint.
You may consider selling the motor to a restorer for enough to do your 454.

The 283 is just a 195HP 2-bbl (got the int manifold also, and a few other parts), it's the original engine that came on the car, but down here original numbers and the such are meaningless, my guess is i can get maybe 200 us dollars, 250 at the very most, since it was stored indoors and is in perfect condition.
As for overbore i think i can go .030 (haven't measured yet) but since all parts must come from up there (and are really costly) going .060 was a safe bet...
Anyways, posts so far lean to the 427 option, not sure about rect. port (LS-6 type) heads, won't they kill low end torque?, i've been told oval port heads are far superior...i'm open for suggestions since i have peanut por heads (useless), and BB's engines are nowhere to be seen here (even SB's for thast matter!!) so most parts have to buy new.
Thanks

.60 would be safe jsut make sure u have breaters and stuff.

the oval ports are definitally for bottom end. however if you want to crank out some horsepower bolt on the rectangular ports.

Some things you need to consider about your twin - turbo plan....

If you want to make any real power out of it, and you want to be able to tune it effeciently, you'll need a fuel injection system.... So you have to factor that into the cost.

Ive seen turbo's on carb'ed engines, and it just doesnt make the power it should - as well, its hard to tune unless you install a stand-alone wideband O2 sensor, and even then, you still will never have the precision of being able to select a specific A/F ratio at a given RPM.

And what about an intercooler? More $$$ and more headaches trying to clear the piping from the hair-dryers, to the IC, and back into the intake manifold.... BOV's, wastegates....really, I can make a huge list that'll make your wallet cry, and you can't go cheap with turbos and expect it to last

Anyways, Id stick with a 454, not the 427. Ive had experience with both, and you will have more fun with the 454... And even a mild one will make more than enough power to shred that M20 to peices in a matter of weeks, so be careful.


Oval ports are great for the street; Square port heads will cause a noticable loss of low RPM power in engines that don't have enough cam/compression/rpm to support them.

To quote an excellent engine builder "Horsepower sells, but Torque wins races", so concentrate on building a good torquey engine that you can have fun with - don't fall for the "bigger is better" trap when it comes to cams/heads/carb/compression, as it doesn't apply to STREET cars.

Good Luck.

Well, think I'll stick with the BB, all the parts needed for the TT install were taken into consideration and are available here at reasonable prices, but the BB will be easier to build, and besides it'll still have some room to crank some more power down the road, I'm guessing fuel consumption will be close to the 283 also.
I planned on a 427 instead of the 454 to lower torque a little, don't want to be breaking thinghs on a regular basis, I do have the original crank but needs to be turned .020 .020, and is a cast unit (casting 353638), you can find a NOS 3.76" stroke forged (plenty strong) crank for less than half the price of a nodular 454 (big plus), and I also like the higher rpm potential, but still open to suggestions here.
As far as heads go think I'll go with ovals.
Thanks

Build the big block as a blower motor...top it with an 8-71..go with the Electronic injectors with the Enderle bug catcher..install a tubular front axle moved forward a few inches....and move the rears forward 10-12".......an Altered Gasser......wheel stander...........

sorry BlueDSM but i dont agree with u, turbos can take alot $$$ but i did many set ups with less than 1g .but i also have to agree with u.. been a diehard carbuator fan turbo and carb sux done my first set up with tpi and love it wish i done it b4 but if u dont to the work ,turbo will eat ur $$$ away if u do most of the work u will be fine ...used parts in good shape and alot of shopping and time will help alot.... and i would go for a bb tt >=)