The Mustang has
5 speed Tremec with the .64 5th gear
power brakes
air conditioning
3.50 rear gears
245/45 17 tire
Here was the old motor with a broke crank!!!
Using the Wallace racing engines calculator, the static compression is 9.74 to 9.84 depending on deck height of .005 to .0 using the 11.7cc value.
Edelbrock RPM with a 750 vacuum secondary converted for 4 circuit idle. I do have a BT 2X4 for down the road at a later time.
Cam is a Comp Hydraulic roller – Lift is 574/574. Installed at 106 Intake centerline, Duration @ .050 is 227, lobe separation is 112. From talking with Comp this morning, it could be reground. They could move the duration and or lobe separation a few degrees. The lobe could be increased about .010 for a new lift of .591.
Duraspark distributor with factory ignition box
Timing chain Ford Motorsports with 9 position keyway
Standard volume oil pump with ARP drive
Head gasket Fel Pro 1020
Cylinder head – Felony heads from Barry w/ 76 cc chamber, adjustable rockers and POP’s end stands. I might swap over to nonadjustable rockers and new pushrods.
Bore 4.11
Piston Sealed Power 381NP-.060 over - 10.33 to 11.7 cc depending on where I look.
Pin dia. Stock .975
Compression distance 1.66
Crank Stroke 3.98
Rod length Stock 6.488
Deck height 0 deck to .005 in the hole according to the Machinist
New motor
With only 6600 miles prior to crank break, I will reuse most of the parts I can. I do have another 390 block that should clean up at maybe .020, definitely by .030. I will buy a new Scat crank and rods and I’m leaning toward the 4.125 stroke. It gets me to 429 to 431 depending on bore clean up. I want to be in the 9.5 to 1 range for compression. The block will get decked to help achieve the right compression ratio.
Would the difference in stroke (4.125 vs 4.25) make a big difference in the scheme of things?
Is there a better selection of shelf pistons for the 4.25 stroke vs the 4.125?
What would a ballpark price be for a custom set of pistons?
If the cam is reground to something different, what should it be? Is it worthwhile for the additional lift?
The intended purpose is to drive it. We drove it to Adrian Michigan for the Mustang Steve Bash with the crank breaking on the way home. The 2020 Bash will be in Surfside Beach South Carolina and I intend on being there. The car was a lot of fun to drive, it pulled from 1000 RPM in 4th gear and never bucked. 1600 RPM was about as low as it would go in 5th gear before it started to act up. The next motor needs to do that too.
Thanks for the help.