Big Block Install


New member
I'm thinking of getting a 420cc 13 hp predator engine to swap out for my clone. Has anyone done this before, I'm wondering what is involved and what ill need to do to make it work. Is the footprint the same? and I know the crank is a 1" but don't know if it will line up too.
you will need a large topplate for your engine mount . yes the engine foot print is larger than the mall block . and you will need a 1" clutch

burris racing in california , and Laukatis racing in illinois bolth have verry nice top plates for the 390/420/440

i am a clutch dealer for i also run this engine as do alot of my friends we are all one 1" Jammer Eagles let me know if i can help you . i can sell you to you under the listed website price call 618-797-8896 post or pm
Your choice of mounts depends on your application and size. Look at the PFM mount as it moves the engine further away from the seat for bigger drivers.
We also carry a pretty fair amount of parts specially made for the predator 420cc motor in which many fit right on the mentioned 440 motor.
We have Billet Connecting Rods, Adjustable Billet Flywheels with or with out a starter gear available in standard diameter or 3hp diameter and top plates with fule pump mounts and throttle hook ups for the 390/420. @ ARCRACING.COM
I just recently tore down a HF 420. The govenor is in the side cover and is very easy to knock out and run a 1/4 setscrew in the hole. The ports look very good so I didn't bother them. Lapping the valves is a must, you wouldn't believe the intake. I read somewhere that 10.8 springs would fit inside the stockers. They seem to work ok onthe bench. The motor comes with 3 carb jets so without some field testing I don't know which to run. I reworked my air cleaner and will build my own exhaust. I've got a Hillard Extream clutch mounted but things are going really slow.
I found a noram clutch I want to get, it has a lower engagement speed. Bandit what was wrong with the springs it came with, I thought they were the 55lbs, unless im wrong
I'm sorry I didn't make myself clear on that, the 10.8 springs go inside the stock springs thus creating a duel spring setup.
Parsons has pistons in stock. We ran stock pistons at Daytona with no failures even though during one race cyl head temps were over 500 deg.