I built a 512 for my Super Bee last year, and here are the basics:
.040 over 400 block.
Source 4.25" stroke bottom end with the lighter crank and upgraded rod bolts.
TF 240 heads, Scott Brown solid lift cam, Hughes 1.5 rockers.
10.6:1 compression.
I read a bit on intakes before I chose one, and then put out the word looking for an M1 or a Holley Street Dominator.
A friend thought he had a SD, and it ended up being a Performer RPM, so I picked that up. Then I found a screaming deal on an M1 single plane. I put the M1 on, but got to talking with Cab Burge and he says the RPM would be a better choice.
What do you all think? I am pretty sure the M1 gives me more hood clearance with the N-96 air box, but I know an RPM will fit, I had one on the previous 383 that was in it.
It's going in my '69 Bee, 4-speed, 3.54 Dana. Suspension will be switched over to either Assassin Bars or Cal-Tracs once I get it all back together.

Imo, the rpm will be much more responsive and street friendly with those 3.54 gears. You have them both so its easy to try them both. But I think for the street you will like the RPM best. It might even be the best choice for the track as well since you have a 4 speed and not a mild stall vert with a automatic.

M1

ITS A 512 CI MOTOR

two inch spacer help out with a 850 carb

I have ran the M1 on my 512 (400) for going on 4 yrs now. Throttle response is a non issue. It is great at low, mid and full.

Last yr I switched to a 4500 version of the M1, no loss of throttle response on the street but it is .12 faster in the 1/8. I hope to get to run some 1/4 mile times this yr.

With the 512 there is so much low end torque I dont think you will notice any let off by running a single plane.

PHR did a B series intake shootout a few years ago that you’ll find if you google it. It suggests that those two make similar HP up top, but the RPM will offer a much broader torque curve and better power down low. With 3.54 gears and especially in a big street-heavy B-body, what you need is midrange torque. My sense is the RPM makes more of the meat your car needs. I run one on my 452” B motor. Last fall I added a short 1/2” open spacer and blended the top of the intakes carb-pad in an effort to open up more plenum volume to each cylinder. Although I didn’t do a back to back test, I noted that the car felt like it wanted more RPMs and made better top end power. It went faster but the air was good, so...??

On a 512 go with the M1. On my old 440 with 3.55's I had the same question . There was almost no difference at the the track or on the street between the two intakes.

Very true.

I guarantee neither will fit under my hood with a 2" spacer.

I was hoping someone had some real world experience with it. I was thinking the torque should be a non-issue, but I was concerned about the 3.54's.

What gear do you run?

Thank you.

I run 4.10’s with a 28” tire. I’ve toyed with the idea of an M1; I’d be interested in your results if you were able to do a back to back test.

I'll see what I can figure out. I'd like to switch them on the same trip to the track and see which one performs.

I run a small Comp Cams Mech, grind XS282S. Like Stealthwedge67 I also run 4.10 and 28" tires and my car is 4000lbs.

Going to try and get something closer to 29" tall tire. The convertor on my car is tight enough that when I drive on the street that when I left off the brake it moves w/little slippage. On the track when I mash it it flashed to 4500. That is a little higher than I wanted. Was wanting closer to 4-4200. I shift at 5500-5600. If I'm running 1/4 I cross the stripe at 6100. I wont return my convertor because its too conmsistent. But I will be trying one another one from PTC that is a tad tighter to see if I can even out the shift points and finish line rpms.

The edelbrock is a great intake, my brother runs it in his Cuda w/the same cam I do. Only difference is his is 446CU and I'm 512. Which ever you chose you will like. The 512 is a great set up.

I was planning on going with a 29-30" tall tire. I plan on driving it a lot, so I will be attempting to keep the revs down. 295-65/15 is my tire of choice, but it is only available in drag radials and the super expensive flame-tread Mickey Thompson tires.

Really don't see why a RPM would even be mentioned on a 512?

Von, the RPM is a great intake for the street No matter what C.I on anything that has less than a all out solid roller cam with 440 size port heads
I've dyno tested multiple RB and B motors with a bunch of different intake, the RPM is the best over all for low RPM HP and torque, especially with light part throttle driving below 3500 RPM
I haven't done any same day at the track tests on BB 440 intakes in a long time so no valid feedback on that

Fathers Roadrunner:
Going from an RPM to M1 produced cleaner and more consistent plugs for all the cylinders on his pump gas, FT cam 440. With 3.23 gears and a 9” convertor it still kills the tires on the street.
He went to a Holley SD but swapped to a larger cam at the same time. It was a 12.0-12-teen car with the RPM and smaller cam. With the single plane and larger came it’s an 11.90-11.98 car @ 112-113 car.
91 octane
3900 pounds


My Coronet:
On my 505 with Eddy RPM heads, flat tappet, 93 octane I went from the INDY 2D dual plane to an M1 4150 ( STD port )
I’ve hit 11.05 ( peddling on top end ) and 11.06 and some other 11.0’s @ 120-121 ( Close to 122 once ) with 3.54 gear and the single plane.

Couple of the passes have been 6.99 and 6.98 in the 1/8 with the M1

11-teens and some 11.20’s with the exhaust still on and the M1 but 118 to high 119 mph

Does pull 24 MPH from the 1/8 to the ¼ on some of the passes.
While bracket racing, I noticed that peddling on the top end with the single plane does shave off et as much as peddling with the dual plane.

3840 pounds with head pipes and mufflers off.
3900 pounds with mufflers and head pipes on.
Sixty foot has been 1.54 best and as high as 1.58 with M1 and 3.54 gear
Flat steel hood.

FWIW

Mike

I still venture that overall...a RPM is a choke on 500 plus inches, unless we are talking a super heavy/pulling type application.

Silver,

Exhaust is costing you a solid tenth, (maybe .15) , it looks like?