How much can 241's be ported safely?
 

I started on my porting and polishing project last night and it looked like the intake walls were pretty thin stock. I was able to port match them and smooth out the rough texture but I didn't want to take too much material away. I think these heads will make some good power, I'm having them milled
.018" in order to get 10.5:1 compression. What has been the best as far as flow numbers are concerned that people have achieved with these heads?

hears the flow numbers for my old 241 ported by Lloyd Elliot

int.exh
.050... 44-34
.100... 74-57
.150...110-76
.200...142-92
.250...174-119
.300...207-135
.350...235-154
.400...254-174
.450...273-190
.500...286-201
.550...302-213
.600...311-227

now i have some dart 225's that are ported,and flow a lot more than these

Dont open them up to much because you will lose air vilocity in the intake runners, which is needed for small displacement engines(5.7). All I did was clean up the walls to make them smoth and blended the bowls.

So how well did this work for you?

I didnt bench flow the heads so I have no idea what they flowed. I also changed my cam from a 224 114lsa to a 232/234 112lsa. With the heads that I ported and the cam I picked up 45 rwhp at 6500 rpm. I lost about 10rwhp under 3500 but that cam is supposed to make power at high rpm. The tuner said I probably wouldnt have lost anything if I milled the heads but I was affraid of ptvc. I should have milled the heads and used a thicker gasket. :devil:

... all the way to accomodate a 2.100" valve.