Thanks guys, Campbell looks to have the best advertised prices for Molnar stuff so once I'm back in town I'll definitely order from them. I also called Callies, they weren't sure if a 4.375" crank would fit with the internal pickup, but did confirm a 4.25" fits with no issues. I looked under the car again and I only see one potential routing for an external oil line next to the block, because of where the steering box mount is a taller oil pump or one with a sandwiched plate like the Milodon setups won't fit. I could maybe route a -12 line up to the inlet on the block with a 90* fitting but it's going to be very tight.

Originally Posted by Streetwize
If it were me and you have to run the smaller headers you need to up the compression and reduce the overlap, build more torque sooner and lower the RPM peak...Kinda similar to if you have FAST Racing type exhaust restrictions....

As small as 1 7/8" x 3 1/2 with a 3" system sounds, I'm sure some of the FAST guys limited to Manifolds and 2 1/2-ish(lol) would kill for the ET gains they might make having the exhaust system you're working with.

Also the 40-50HP difference/advantage with open headers on a Dyno is likely to be considerably reduced in an actual car with full exhaust pushing against rolling and wind resistance.

To me a big C body is going to ET better on FAT mid range torque, it's going to make it's best moves through the middle and on the shift recovery and it's simply not going to top end charge like a lighter car with a lot less frontal area.

You want a big grunt motor not so much a 'horspower' motor.

I got a ported MW Indy Dual plane if you want to borrow it to try it out. I'd run it over a single plane on something like your 68

Unless it's in a really light car like an A body, to me a BB Mopar is less like a Hemi or a Small block Mopar and more like a Buick/Olds/Pontiac type motor, and the ET's respond to a similar kind of race tuning.

Also if you look at your exhaust sytem I would put the 3 1/2" collector on it and bring it straight back and run your "street" system coming out of the collector extention on a 45 degree cut out branch on each side. Forcing your exhaust through that 'double dog leg ' just to get to the cut out is killing some torque and power.


This makes a lot of sense, thanks. I definitely want to put as much compression in it as possible. I'm sure I could get by with 12.5:1 on the street with some timing pulled out of it but that will also make it lazy and also run warmer than it would otherwise.

Definitely think I'm going to need a tighter converter. The converter in the car now flashes to ~4500 on motor and maybe 5000 with a 180 shot. Even if this new motor only makes 700, I think that's a solid 100 more than it currently makes on nitrous and should have a similar torque curve too.

Agree totally on the location of the dumps, make the open end have flow priority and then let it make a 45* turn to join the rest of the exhaust.

Appreciate the offer on the intake, honestly I'm probably a year out from getting the motor in the car. Originally thought I'd assemble it myself with help from friends who offered, but am getting gunshy now adding up the receipts of what has been bought already and what it still needs. Might start contacting some builders.

'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118