Which combo would win a race?

tmoss said:

I haven't done this (yet), so what is required? Do you have to relieve the cylinders at the bottom for the rods?

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Tom, yes you have to relieve the bottom of the cylinders for the rod bolts(ARP 8740 cap screws) to clear properly. I was always told .060"-.080", I like to go .100".



I am torn on this topic, I think the 347 is better in the long run, but with what you have right now the budget 306 will go faster since you have better heads and supporting parts. I would look at a stock replacment aftermarket rid, you can get a cast SCAT for around under $200 and it already has the ARP fastners and is better then a stock rod, espeically one with a lot of miles. You'll need to rebalance it but if your shooting for 10:1 your goig to need different pistons anyway, then you can get a full floating pin design.

Like 25th stated if you race in a local class or track series you may want to really look into it so you don't build something that will put you in a class you can not compete in.

Just put better heads on the 347 down the road.

Well the 347 leaving harder off the line doesn't matter to much because 95% of your trip down the track will be above 3500rpm...just where the AFR's and cam come into play

90mustangGT said:

Thanks everyone. The reason I am torn is for the same reasons you all have given me to build the different combo's. I belive the 347 would leave hardest off the line but the 306/AFR/CC combo would then play catch up. I think when I finally got the 306 fully built thought I would kick myself to think of how much I would be making with a 347. It least with the 347, I wouldn't be re-modding, I would just be replacing the only thing still stock under the hood.

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You're right. Once you put some real h/c/i on that 347, you'll forget all about that tiny 306 and you'll make it look like a civic Once you throw some TFS hi ports, vic jr's, afr 185's with a TFS R intake and a custom cam and your making like 425rwhp with the potential to run high 10's on motor you'll laugh at your self for even considering a 306. The 347 is your foundation and you can improve it down the road as money allows. I agree 100% that to go all out on a 347 now is very very expensive. Thats why I bought the Vortech SQ but even that wasn't 'cheap'. I'm hoping the 450-475rwhp will make me forget about the $2300 I just spent Good Luck man.

Mike

Your other option could be do the 306 now and be happy and then add a novi 2000 or a vortech S trim down the road when you get power hungry again. If your gonna do a 306, I personally would use a TFS TW or an AFR 185. Pick the head first so you can run the proper piston and decide if you wanna boost down the road or not. Tough choice dude..