Question for you Sir,
Reading threads here for a while, and you seem to be the guy with the info. I've got a '70 383 in my powerwagon, and from what I understand, it has compression somewhere in the 7-8:1 range. It has 906 heads, and it's a daily driver. I found a set of 906 heads for $125 that I want to port. I want to get a 906 head that's cracked/no good and practice porting so I can see how far I can go before hitting the water jackets. I don'twant to spend $ on a flew bench to see if I'm improving flow, does it make sense to just hook up a shop vac and have a sensitive vacuum gauge in some pvc in between the shop vac and port to determine if I'm making improvements in flow? More flow would be less vacuum?
Thanks for all the info here on low compression engine set ups, super informative.