Cams, heads

[Rusty McNeil]

Does anyone know if the .428 cams are going to be a big difference from the .380 on the street, driveability, noticebale difference in idle, loss of "low end friendliness" etc..............????

See my "Motor Work" post for what engine it's going in, Essentially it's about as radical as you can go I think, 13:1, 1540cc, stroker crank etc.... if I go with these .428's it's going to get heavily ported and MAX size valved heads with shim under buckets as opposed to stock ported heads if I use the .380's.....

I want the mostg possible out of this engine but have kinda shot my wad already and am trying to decide if another $2 grand is worth the gain...

I'm hoping for around 175-180hp, not sure if it's going to get there without the big cams and heads........I'm thinking if a lower compression, smaller cammed, smaller stock valved and less ported tourmaster will make 160-165 then those numbers should be attainable with the build I'm doing...... I'm using stock carbs too for now, just stage 7; changing those is another big pile of money I don't have right now, as it is the wife is shitting bricks already.:bang head:

Thanks in advance....

 

[KJShover]

I'm running the Stg. II from Megacycle (.354" 254?). The midrange is noticeable.

I'm thinking your have some improvement in the midrange, but see more of the increase in the higher RPMs.

 

[355cid]

I was just wondering how much lift, duration and piston dome a person can run until you really have to start worrying about valve/piston intersection with the Vmax combustion chamber design?

 

[Rusty McNeil]

I was just wondering how much lift, duration and piston dome a person can run until you really have to start worrying about valve/piston intersection with the Vmax combustion chamber design?

I dunno exactly, but the .428 is a proven fit in the bike with the proper piston,.Acomplishing my 13:1 shouldn't take as much dome since it's stroked 5mm, and they should have valve reliefs to accomodate the biggest cams around. Absolutely clearance does need to be checked on assembly tho'

I think the .380's are the biggest you can go on stock pistons...