The M1 4500 actually works well, big plenum combined with nice turn radius to the outboard runners.

To be a real test of the manifolds I might have run a bit bigger cam, with small ports and a big manifold it'll want a bit more cam timing to really feed the holes up high and TAX the runners to see what they can really do.

I'll give away a nugget here...what I find works well on strokers is going bigger on the intake lobe and phasing it early (like for yours maybe a 270/276 in at 102-104). I discovered this years ago that big U/D solid cams always made MAD POWER in 500 BB's....108 center cams that were often factory ground +6 for a 102ICL....one of Harold's pioneering 'tricks' that worked very well with his ramps. The assymetric lobes (I believe) actually advance the ICL slightly compared to asymmetrical lobe measured at the same .050 up/.050 down but advancing the cam (especailly with a roller) seems to work as well. The early center gets the cam up "big" earlier in the Cycle whan the big arm is trying to fill the hole with air, also by advancing the cam on the other side the closing event is sooner making the cam act 'smaller', but also remember since a long stroke comes back up the hole at a faster rate per degree of rotation, you give back more effective displacement per degree after BDC..I never liked 108 ICL's on my big arm stuff...if it works great....to me that means the cam is still probably (usually) ~10 degrees @ .050 smaller than the motor really wants. The bigger cam phased early will make as much powerband torque in many/most cases plus also make more power up high with no trade-offs.

The HUGE advantage of a roller, especailly in an under-ported 500" BB or even SB wedge is the valve can hang around at or near peak lift longer than a FT..this is true for ALL motors with a roller of course but with a stroker the piston speed is higher at any given RPM so it has more hole to feed in the same amount of time.

works for me...your results may vary