I'm starting to look for a blower for my 34 Dodge coupe. It will be A 671 or an 871. I'm not sure an 871 is a bolt on with the distributor where it is. Is there room without too much medication? Also, What brands are recommended and/or to stay away from. TIA
Arno

Stay away from BDS Call Littlefield blowers at 714-992-9292 and ask them about which intake manifold to use on your motor for a 8:71 or even a 10:71 The bigger the blower the slower you will need to turn it to make the same amount of boost, slower turns equals less intake manifold air temps
On your deal if you want it for looks mainly and don't really care to have much more than 7 lbs of boost(probally around 600 HP on 91 octane pump swill at 6000 RPM ) then go with the big bore 6:71 case

Kevin

Thanks for the reply! Can you tell me what a big bore case is?

I can't tell you the exact size differences internally between the standard case and the big bore case because I don't know that
I was ask to inspect and tear down a street driven blown BB(454 C.i.) Chevy years ago, it had a small bore BDS blower on it with two Holley 650 D.p. carsb on it. I had called BDS to find out what is was and I was told off the information they ask about it that it was a small bore 6:71
That motor made 620 HP at 5 lbs boost on CA pump swill back in the late 1990s, I hopped it up some, cam change, pulley change and carb. size change and got 780 HP out of it with 7 lbs of boost, NOT GOOD
I built and dyno tuned a blown 484 C.I. gen 2 Hemi with dual 1050 CFM Dominator carbs. with a Littlefield 10:71 blower, that motor made 920 HP on CA pump swill at 7300 RPM with 7 lbs of boost It made 1027 HP at 6500 RPM with 12 lbs boost on race gas going into detonation If you could mount and safely use (clear the distributor or run a crank trigger ignition)a 8:71 on your motor that would be better than the smaller 6:71 )
You can turn the bigger blower slower to make the same amount of boost with cooler manifold inlet temps. which will make more power due to the cooler denser air with more fuel mixed in it

Don't get suckered by boost numbers.

Boost is a resistance to flow. Good flowing heads and a proper cam will show less boost than poor performing components with the same blower and drive on the same bottom end.

I made more power at 8 psi with the Eddy heads and good intake than I did with the iron heads and Torker intake.

Also it is a PRESSURE measurement, not airflow. X PSI with a 6-71 is less airflow than X PSI with an 8-71 because the 6-71 is producing more heat. You can heat air up to create pressure, but you will not make more power (you'll actually make less) because there is no additional airflow.

I have a friend with an 8-71 on a 392, lightly ported heads, 240ish duration cam, he made around 650 HP @ 8 PSI and similar torque. Engine has 2 750 DPs on it and its VERY responsive.

what he said...I love when guys talk about running this or that boost. It's just a measure of resistance, you want air flow. From what I understand those old Hemis like boost. A 671 will work, but an 871 will work better and w/ less heat and stress.

Just depends on where the priorities for the motor are.

If it's primarily a street car and the blower is mostly for "show", a 6-71 will work fine on that sized motor.
With a properly designed build, an easy streetable 600hp plus.

Go straight to the 8-71. The 6-71 will work but you'll find yourself pushing it near its max.

Thank you!