420 Predator Jetting Help
- Thread starter DRC21
- Start date
poboyracer
Member
Try around 32 pilot and 62 main and adjust from there. Shoot for 350 to 380 head temp while on the track.
Big block 460
Member
Hu???? A 32-62 on a big block running methanol ..... nooooooo....I don't have a clue what carb you have or what jetting your running now ....but those numbers sound low even for gas ! Hmmmmm...WAIT.....oooohhhhh ...it's a stoc carb ....actually that might be close ....????????. But yea that's a good question tho ...one I am actually on here looking to get answers to myself ..I am running a460 with 450" lift and 15:1 compression ratio ....with a 34mm mikuni tm .. anyone out there that can help ? The tm carb is new ..the same engine with a vm34 mikuni on gas jets has a 270 large hex main and a 35 pilot ...any way to know what methanol jets I would run ? Is 50% larger jet size right ? Hmmmm ....help
70mm stroke, 90mm bore, head shaved .100", head o ringed, .032" copper head gasket. Do the math.
Im not saying mr big block 460 is there, but those are the numbers im working with right now. It is definitely possible
Big block 460
Member
Welded head ! Milled .085" 92mm piston and 70mm stroke ...22 cc chamber .010" head gasket .020" in the hole ...4cc valve reliefs....it's actually lowered to 15:1 ...but yea your right !! It takes a real man to get 15:1 ...lol....most don't go there ! Watch my videos ...Paul's karts ...on you tube ...serious **** !....I still need info on jetting methanol ...is the jetting 50% more or 250% or what ? ...anyone with real knowledge reply ...no guesstimates...
Anyone answer you on this yet? Thank you.
alvin l nunley
Site Supporter
Gas burns best at about 14 – 1 ratio. Alcohol burns best at about 6 – 1 ratio. Adjust your jet size area, not diameter, with those ratios in mind. Rule of thumb; a 100% increasing area. Pi R^2 is the formula for area of a hole.
