Blower motor questions
 

I know this is a little out of the ordinary here, but I know there are a lot of knowledgeable people on here. I want to swap out the 302 with tunnel ram in my Camaro for a relatively mild small block with a blower, but not sure where I should start with the new engine.

Would you all suggest buying a lower compression crate motor, beefing up the bottom end and putting the blower on that, finding a running small block and rebuilding it to blower-ready specs, or just scrapping it all and starting with a bare block and going from there?

I can only afford to do this over time, buying some parts with each pay and finishing this over six months or a year. Appreciate any thoughts/expertise you can provide, thanks.

Are you wanting looks or performance out of the blower?

A little of both, but it'd just be for cruising and not really any racing.

Which blower are you looking at getting?

I was thinking a 6-71 or some similar variant, but I've just started researching the entire thing, thanks.

No suggestions where to start?

Sorry.. Forgot about the thread. I would go with a forged internal 400ci +/- sbc if you are wanting to going with a 6-71. Nothing crazy just a good set of rods & bolts and a set of flat or dish forged pistons. Heads will dictate which piston you will want to go with. You need to figure out what kinda budget you plan on working with and go from there. There are a ton of options out there. You will more than likely have around $5K minimum in just the blower and everything itll need to make it work.

Thanks Darrell. I figured it would be pretty expensive. Any reason why a 400-ish instead of a 350? Just curious, thanks again.

Hi Mark, FWIW I'll give you a brief summary of a sbc I built +25 years ago. The engine was going in my 28 Ford Sedan Delivery and I didn't want the carbs, scoop or air cleaner protruding out of the hood.

Therefore, to achieve this goal I selected a B&M 144 blower which, back then had received good reviews. I started with a seasoned 4 bolt main block, steel crank and GM 'pink' rods. For the camshaft we went with a 'blower cam' and valve train recommended by Comp. IMHO a blower cam is essential for obvious reasons. The forged pistons gave me a CR of around 8.0:1 (I can't remember exactly) and I used traditional GM angle plug heads. A Holley 3310, 750 Vac Sec carb topped it off.

The combination was perfect for the street and with the hood and hood sides installed, none were the wiser. Although we didn't dyno the engine I'm sure it made +/- 350 hp...it started instantly, idled well and would pull like crazy through 5500 rpm with ease. I used a Turbo 350 transmission with a B&M street convertor behind the engine.

Around 15K miles I pulled the blower and sent it to B&M for maintenance. They advised me there was nothing wrong with it but changed the bearings and seals as a precautionary measure for next to nothing. I know most people want the looks (and possibly) whine of a 671 but as indicated above, that was not my goal.

One last thing, I used a Mallory distributor that gave me some 'issues' along the way. If I were to do another blower engine again I would likely use an MSD. As you know, timing is critical and detonation is a killer. I eventually sold the car with around 35K miles on the drive train and other than the Mallory dist. 'issue' the engine ran perfectly.

I hope this helps a little and good luck with your project.

Its personal preference more than anything. Lord knows there are many out there that run a 350ci with the 6-71. Also you will have to underdrive the shit out of the blower by 30% to make the minimum boost of 6psi. And with 6psi your effective compression ratio (with a static compression of 8.0 to 1) will be 11 to 1 give or take. Itll probably be a slight turd down low until you get under boost but you probably wont notice it much on the street. If anything a gear swap in the diff may help. Read through this if you havent already to help understand blowers and how to select the right one for what you want.

http://documents.holley.com/techlibr..._tech_info.pdf