so i am thinking of swapping a big block in place of my 305 chevy motor. I got a 84 monte carlo that needs more power. I was thinking of taking the easy way and just get a 1500 dollar crate 350 but it is only about 260 horse , a giant improvement over the little 305. so should i stay with small block or go big ? fisrt off how hard is it , any major modifications ? WHATS better chevy olds pontiac ? any ones to avoid or seek out ? also price whats a good price for a core and whats a good price for onr that i can verify by hearing it run? I know these are alot of questions but never messed around with big blocks so i am doing my homework before i get knee deep into something i wont finish.
big block pros and cons ?
- Thread starter gwhiz
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ANY big motor is better than a 305. But a Chevy would be the easiest/cheapest to switch over.
I'd go big block just on principle. I am NOT a Chevy guy, so I don't know the ins and outs of a SBC to BBC swap, but I can't imagine it would be that difficult, it's been done before. Of course a SBC crate motor would be the easiest, but once the work is all done and you've got a big block, you'll have something cool that not everybody has. JMO.
well i'm in the planning stages of doing the same thing plus adding a t56 trans in my 79 bu wagon.
the bbc is a bolt in swap, hood clearance is the only issue besides headers. Actually f body headers from the early 70's work better than the g body ones. a 2 inch cowl might be all you need for hood clearance. getting the wheel hop to stop though is another issue with all the added torque you're gonna have, but boxed trailing arms with poly bushings help tons. I say go for it if you have the cash.. its a mean build.
the bbc is a bolt in swap, hood clearance is the only issue besides headers. Actually f body headers from the early 70's work better than the g body ones. a 2 inch cowl might be all you need for hood clearance. getting the wheel hop to stop though is another issue with all the added torque you're gonna have, but boxed trailing arms with poly bushings help tons. I say go for it if you have the cash.. its a mean build.
anything bbc is gonna be more costly, a 454 from the 70's work great, also anything from the mid 90's is good too, vortec 454 is a roller cam stock 400 ft lbs torque and 290 hp, i got my 2 454's cheap but anything under a grand is good for a running bbc. all depends on year and condition, too many options to list.gwhiz said:
Just finished a BB in '78 Malibu. The swap wasn't too bad but did require patience with somethings. Mostly the headers which took a few hours of grinding to get the clearance needed to bolt them up to the heads because they didn't clear the head bolts. So if I would have known could have ground a little off the bottom before they were in. You have to set them in and tie them back then set the motor in. I don't have a A/C Heater box which made the install a little easier. After it was in it looked smaller than sitting on the crate 
My dad and I would work on it 5 or 6 hours each weekend for about 5 weeks and wouldn't get discouraged when we hit a little bump in the road. Finished it a couple weeks ago and just put a little over 500 miles on it last week at Crusin' the Coast. This was our 1st BB swap and after finished it was all worth it and would do another one.
My dad and I would work on it 5 or 6 hours each weekend for about 5 weeks and wouldn't get discouraged when we hit a little bump in the road. Finished it a couple weeks ago and just put a little over 500 miles on it last week at Crusin' the Coast. This was our 1st BB swap and after finished it was all worth it and would do another one.gotta replace the front coils for the extra weight and make sure you have a big *ss radiator.. other than that your good.
Cooling of course, as well as weight issues. Need more spring up front. And something for the smile-itis you will have when punching the gas pedal. 
gwhiz said:
I am running a 3100cfm electric fan and a 160 thermostat. Made some rubber flaps for side of radiator to direct air flow thru radiator because alot was passing around the radiator. I also put a extra fan on front side of radiator on a switch just in case but I sat in traffic this weekend with it and never had to use it in 85 degree weather. I have a Gen. VI BB which run a little warmer but it never got over 205. As far as weight I am only about 150lbs more than a sb, I also have aluminum heads but even a cast iron can't be more than a couple hundred lbs. more. Google big block in a G-body for more info and anything I can answer since it is all still fresh in my brain I am more than happy to.
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