I watched a buddy of mine go 11.2 at 122mph this weekend with a 331 in a fox hatch. It has a TFS bos R intake, TW 205 heads, a comp 274 (I think) cam, and he was hitting the rev limiter right before the finish line at 6900rpms (he has an extender). Its a well thought out combo that EASILY has more in it. he's switching to a 90mm TB and a few other little tricks.
I somehow doubt it'd be that fast with a 306.
You know when I was shopping for parts...quality parts are the same price really when you go 306 or 347 crank,rods,pistons...same price. Now if you use stock parts and just to machine your old parts and get new hardware the savings are minimal. And you are still using stock parts...I went with the 347 really the only other cost in building the 347 is notching the block but then again if your pinching pennies you can do that your self. I dont know as for me I got the cubes. and as far as reliabilty, well we can toss it either way ,earlier 347 did burn oil after a couple thousand miles but with proper rings that is a thing of the past. As for tuning its a N/A combo it cant be harder to tune than a blower.
As for me 347 with T/W heads -Trick Flow R intake. Comp cam.
There is no argument here, opt for more cubes. There is no difference in cost so why lose out on the extra cubes. The 331 vs. 347 rod ratio driveability myth has been put to bed years ago. You put the same identical parts on the same identical block and the 347 will be a bit better.
when they tested the box r with the TW 185s on a low comp 331 it was worth 12 hp going from a 75 to the 90 that the box is suposed to run
I am still tossing around the idea of whether to do the box on my 347. I think i am going to stick with the holley but i would like to try the box out for sh its and giggles
that cams seems small for revving that high, does he have it retarded? the 282 might be a ncie addition too.
Your right Davis, he was running the 282 but I think he told me he just swapped that for something else too. i'll try and find out what cam he is running and let you know just for comparisons sake.