Two part question about my heads, and 383

[sam's 72]

I was just about finished with my engine. I have every thing bought, all machine work done. all that needs to be done is assembly. At the last moment I decided to go with a different set of heads. I was going to use the alum L-98 vette heads, bigger valves installed, and ported and polished. I am thinking about going with a set of Dart pro 1 alum heads with 200 cc intake runner.
this is what I am building if some one would run a dyno useing both heads.

383
10.3:1 compression
5.7 inch rod
Comp cam Hydrolic roller
276 advertise duration
.502 lift intake side
.510 lift on exhaust side
going to use 1.6 roller rockers
Eld air gap intake
750 holley dp
I would like for some one to run numbers useing both set of heads, the L-98 heads I have flowed 227 on intake side, can not remember what the exhaust side flowed.
I can get these heads at a really good price, just not sure if it is worth it or not, the Dart Pro 1's have not been ported or polished, they are straight out the box.

Right now I have the L-98 heads ported and polished ready to bolt on. I am looking at buying some Dart pro-1's. If I go on ahead and do this, I am going to port and polish these Dart heads my self. My question is, ( I think I already know the answer ) when I am through porting and polishing, are these heads going to have to have another valve job? these heads will be brand new out the box. Is there any thing I can use to put around the valve seat to keep them from getting hit with the porting and polishing tool? So I won't have to have the valve regrind?
Sam





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Sam