Hello. I have a stock 455 w/a TA212 cam, an s-divider w/spacer, and exhaust manifolds. The motor ias a stock rebuild w/low miles, I don't want to take it apart. It runs a tad like it would like more compression (guessing). Can I take care of this by milling the heads, doing some work & installing big valves? Will milling make the intake fit weird or anything? How much would I need to have removed? I am fine with running 91 octane (CA gas). The car feels great cruising around part throttle(2000 stall & 3.42's), but when I floor it, it is not silly-fast. My previous 2 GS's had 455's with big valves, high compression, & ported pockets & ports. They were silly fast, so I am guessing the stock 73 heads are making the difference. I have about $700 now, and I am considering putting this dough into an aluminum head savings account, but I definetly don't want to mill the heck out of new Al heads. I would appreciate any info., I need more horsies.
How much timing have you got dialed in? You can make a big gain in performance by advancing the timing. Try to run as much timing as possible without spark knock or hot start problems. You will have to run premium gas however. Mike D.
I have about 34-35 degrees total (12 initial, can't get the initial lower w/o dropping the total). I'll recheck, though, it never did ping, but it was high 80's today & the car was almost 200, and it pinged. Thanx Mike.
That timing sounds right. Make sure you check it with the vacuum advance disconnected if you have a vacuum canister on your distributor and it is hooked up. Also, some other things to check. Make sure you are pulling the throttle plates open all the way when the gas pedal is floored. If it has a quadrajet on it make sure the choke is opening all the way when hot. If it isn't, it will keep the secondaries from opening and would cause it to run on the primaries only even when floored. Mike D.
