I have a 79 Lil Red Express truck with a 408 Magnum stroker in it. The specs on the engine are 10.5.1 compression, Edelbrock ported heads, Hughes Hydraulic Roller (Custom Grind); 228/236 @ .050 .550/.565 on a 108 LSA w/ degrees of advance and Crower 1.7 rockers. Has about a 2500 stall in it now along with 3.55 gears. Currently has an Edelbrock Performer RPM Air Gap with a Holley 770 Street Avenger. My brain was wondering with this combination if the Mopar M1 4bbl intake with a rebuilt 850cfm Thermoquad if it would be a better runner in the mid range and up top? Just something I was throwing around in my head at this point.

The M1 is a single where the edelbrock is a duel plane. Duel plane will perform better in the mid range and the single better up top.
https://www.allpar.com/threads/test...agnum-v8-engines.229969/#post-1085224067

There are both a single plain and a dual plain M1 intake.

Personally I'd put a looser converter in it and leave the motor alone.

Thank you all the feedback thus far. I forgot to specify the single plane is what I was considering because of the Spreadbore pattern and no need to run an adapter plus hood clearance too. As far as the converter is I'll have to consider that in the future should I need one.

I don't know much but I'm betting that the capability of the heads is going to affect the outcome with the different intakes. If they are restrictive with respect to feeding 408 cubes, I bet you won't see much difference.

Those Eddy heads are a pretty decent head, especially ported (assuming good port job) so I doubt they will be any restriction.

That's very close specs to the engine I built for my dakota R/T, it had a little more midrange with the RPM air gap than the M1 single plane. The single plane did give me a little more top end butt not much, I actually switched them because it was impossible to hook up and I wanted to knock out a little mid range in trade for more RPM.

Thank you all again. The heads are ported as far as I know. HotRodDave that's good to know about what your results were. I was just thinking with the size of the cam and ported heads that maybe the single plane might better by just a slight margin but, at this point I might as well wish myself luck finding one.