Darkspeed wrote:Out of interest how much bigger than a stock RV8 are the valves in the 300 I have seen mention of huge and also mention of smaller than the mid size valves that sit on a stock rover seat.
chodjinn wrote:The valves on Buick 300 heads are already huge, that's why people use the. They have large cc capacity as well which is good for you TT application. I would probably replace the guides and get some double valve springs as a minimum. Port them a bit while they are off as well, ARP head bolts are a must. I think you'd get away with copper gaskets rather than composites as well but other people know more about these than me.
1.63" intake
1.312" exhaust (from an old V8 forum post in 2009!)
CastleMGBV8 has a set on here, fitted 1.4" exhaust valves which is what you would need to do - lots of gains here. No point porting them any further, just a clean up, plus what else has been mentioned by others above.
Without moving the guide position that the biggest valves you can fit to the 300 heads are 1.775" In. and 1.5" Ex
And the cc of each chamber is more than the 36cc you get from 3.5/3.9 heads (54cc?), hence why they are awesome for forced induction.
The price of a set of sorted Buick 300s is less than a set of stage 4 RV8 heads I believe, due to the amount of port work required on RV8 heads to get them to flow similar to buicks.
But there is an major problem with Buick valve guide : the bore of the guides may not be concentric with the OD because of the production process where the seat pocket and the guide were machined at the same time but not indexed on the guide OD.
I do know that Isky make uprated springs, retainers and collets etc for the Buick 300s and even buying them from the states, cheaper than RV8 stuff over here! Isky are quality as well.
Edit, just found this;
http://www.buicks.net/shop/reference/specs_300-340.html
I've reposted some infor from this thread;
http://www.v8forum.co.uk/forum/viewtopi ... 7a0c22f729
Wotland is very knowledgeable about crazy RV8 modifications.
RIP MGB V8 .... served me well as a learning curve.
R32 Skyline V8 .... this one is gonna be a monster!