big block or small block

trucker677 · #1 10-22-2011, 08:33 AM

Hi guys, I am new to the forum and am looking at 1970-72 chevelle to rebuild/restore. I am wondering what are you guys are running for powerplants, big blocks or small blocks, I have rebuilt several cars but have always ran small blocks but I am going to keep this car for a long time so I really only want to do this all once.
If I decide to run a 454 will there be a huge difference in fuel mileage between that and a 350. I never had a big block before but I see a lot of chevelles have it. I just want the car for friday night car shows and driving on sunny days, it will be laid up during rainny days and winter.

Derek69SS · #2 10-22-2011, 10:41 AM

Between the two choices, I'd prefer a mild cammed 454 with an overdrive trans and something like a 3.31 rear gear. Bigblocks just look "right" in a Chevelle, and if you gear it right and keep it mild, you should be able to get 17-18mpg on the highway and have enough power to have some fun with.

If the budget allows though, I'd suggest a 5.3L or 6.0L LS truck engine instead... they're not too difficult to swap if you use an automatic.

I'm working on an LS1-383 stroker/T56 six-speed swap in my car, but there's nothing cheap or easy about that, and the 6-speed requires a lot of cutting.

Ms Grumpy · #3 10-22-2011, 03:34 PM

I am a small block kind of girl. Not that I don't like the big blocks. Here is what I have.

Dart 400 Short block assembly
Dart 11221111P 72 cc heads with 180 runners
Comp 987-16 1.430 springs
Comp cams hyd roller 294/300 .242/.248 .540/ .562 110 deg lobe.
Comp roller ultra pro magnum roller rockers 1.52
Pro magnum push rods

Dart sportsman II dual plane intake
Holley 770 street avenger
Hooker comp headers 2451 full length
Flowmater 2 1/2 American thunder exhaust and series 40 mufflers
MSD HEI
MSD 6AL2
3.73 gear
3200 stall

It ran 523hp @ 5900 rpm with 513 ft lbs torque

Bdubya · #4 10-23-2011, 12:59 PM

Go for the big block, noones gonna ask you, "is that a small block?".

FlintTony · #5 10-23-2011, 05:48 PM

Ms. Grumpy...That is a healthy small block!

Go for the BB Trucker. I went from a 350 LT1 in my 70 Nova to a 427. What a difference.

trucker677 · #6 10-26-2011, 03:49 PM

Thanks for the input guys, I think I am going to run a 454

flash · #7 10-26-2011, 09:22 PM

I like small blocks but then again I like to drive mine a lot and most big blocks I've been around like premium fuel and my small blocks run on regular.