We dynoed my buddy Nat's 401 stroker yesterday. 4" K1 crank, 6" rods, 4.195" Bore mild 10.4:1 dish piston. Milodon pan and mildly ported Edelbrock Performer AMC's with a ported torker intake. Cam was a custom Comp 238/246 @.050 Hydraulic roller on 109 centers with ~.612 lift on 1.6:1 rockers. Motor was built and assembled by Hollis Page of HP engines and Dynoed by the great guys at Vaseleniuck Engine Development in Denver NC. Dave used to work on Bobby Allison's AMC Nascar team back in the mid-late 70's and is truly a great guy and expert engine builder. Holis, nat and I worked very closely together getting the combination just right for maximum torque and trying to get it "all in" by a reasonable 6000 rpm.

Despite the smallish (more similar in size to Small block Mopar) sized Edelbrock Intake and exhaust ports (flowed about 286 at peak) and only 1 3/4" headers (and tested through the Jeep sidepipes), the motor made at least 500+ lb/ft from around 3400 to almost 5900, peaking at 546 at ~4200 and peak power of 547 @ ~5800. We built this to be a torque monster with wall to wall torque to pull a 'Glass bodied CJ-7 with Dana 44/Dana 60's with 3.73 gears 33" tires and a built turbo 400 and is a awaiting a new Ultimate 9 1/2" converter from Lenny (now that we have the dyno data).

Also the engine flowed +710 CFM off of a mathematical 742 CFM at the HP peak so the VE of this street motor was a very impressive 95.6% at that RPM....again hat was through the mufflers and on 93 octane straight from the gas pump down the street.

I'll post up the dyno sheets as soon as Nat sends them to me.

And what made this a super interesting dyno session is we back-to-back tested a Pro-Systems 1000HP against the new MSD Atomic EFI closed loop system....after a couple "familiarization" pulls, the motor 'auto-tuned' on the closed loop EFI to nearly identical HP/torque curves....so I'm not sure whether I'm more impressed with the EFI....or the Carb! but both performed amazingly well. At WOT the Holley is tough to beat, but the EFI will provide much smoother roll-on real world trasition power and better street manners in all types of conditions.

It's gonna be a Beast, Congrats to Nat and Hollis. and Thanks to Dave and all the great crew at the shop!!

Rock on AMC, nice build!

Got the charts (see attached).

We didn't really tune the carb, the A/F's were a bit fat in the middle and leaner up top. This was right off my 414 that's a bit higher cr and spins up about 1000 Rpm higher, but we wanted a decent no fuss/no miss carbed baseline for the EFI to compare to. If we did jet the carb I'm sure we could have found even more power and torque but we needed time to convert the EFI systems multiple leads. The a EFI auto tunes in it's closed loop to I believe between 12.5 and 13:1 A/F at WOT and 14.5:1 at part throttle cruise.

The torque curve was EXACTLY what we were shooting for, I've always liked these AMC motors it's ironic that it's the first one I've worked on in about 30 years!

Was the k1 2 inch or 2.1 journal, what rods did you use and did it need clearancing?

My engine is a stock crank (stroked to 3.92) small journal chevy 6 inch rods and 4.21 bore, indy heads.

2.1 journal rods took months for K1 to make a run of cranks

Originally we were gonna have Barry Allen offset grind a 401 to 3.8" stroke and build a 421

She's gonna be a tire spinner for sure! Got a pic of the CJ7?

Dave,

Body's not on the frame yet, hopefully within a month.

You would like Nat, his attention to detail ( all the hydraulic and fuel lines were done with industrial stainless 'swagelock' tubing and fittings) rivals your own,

Hard lines are on the frame only.