Hank, a siamese head can easily make 425-450 HP with a 250 N/A with high compression and a flat tappet cam. I've prepped many heads for guys in Brazil at that HP level. They do not use nitro and you don't have to to get 450 HP out of these heads or engines, they have E85 or better pump gas and many street racers down their have much more radical engines than guys run here. So, 350 HP is just as easy. I think you are under-estimating how much HP you were making with yours. Tlowes 250 dyno engine made 300 HP with just flat tops and a 70cc head(9.8-1 compression), so another 50 horses isn't too hard to get by upping the compression to 13-1 or higher and getting more radical with the cam and more head work. Again, you just didn't realize how much HP you were making with what you had.



Class III CNC Machinist/Programmer