[doctorj928]

hey guy i have my engione torn apart to fix a head gasket leak and i have stock c6 289 heads on there now with out the thermactor bump and i have the chance to get some E7's cheap which do you think is better i was looking in the tech section and it looks like it says that the c6's flow better and have smaller combustion chambers so im just wondering what you guys think the valve size is the same also

jeff

 

[tonys10sec306]

if you want to do a cheap swap with factory heads . i would go with a set of milled 69-74 351w heads

 

[Freddie]

Don't waste your time with the E7 heads. The ported C6's are a much better head. By the way do you have photos of the C6 exhaust work???

 

[doctorj928]

i diidnt do any exhaust work to them but i did decide to keep the c6 i was thinking about gasket matching them to the header gaskets but wasnt sure how far i could take them out or if it would help all that much im not going to be running them much longer this motor is getting work out so im going to build a stroker this winter

 

[Freddie]

You don't want to gasket match the exhaust side you need a little step to stop reversion from blowing the exhaust back up the port. With the stock 1.46 valve keep the exhaust exit at about 1.1 x 1.3. You said the exhaust had no thermactor bumps but I thought all C6 heads had the bumps.