Well I decided to set up a set of 4.62's in place of my 4.11's and I was happy with the results but left with questions. Previous best was a 1.59 60' 7.30@93 1/8 and 11.53@114. New time with 4.62's are 1.55 60' 7.27@93 1/8 and 11.52@114. First pass was 11.62 @112 and found the 3924 plugs were fouled bad from lots of street driving, so I cleaned them with a stainless wire brush and the car picked up to the times listed. I shift @ 7,000 and trap at 6,900. I shifted at 6,600 and the car slowed by .004 and 1 mph the whole way through that pass. The car hooks hard and Im just guessing Im out of hp. With those 60' times dropping .004 I was hoping for an 11.40ish. First step is changing to a new or different set of plugs like NGK's possibly. Thanks in advance for any advice guys. Coop
What kind of fuel are you running? Which 3924...just the regular plug, or the 3924R? I was running the 3924R's with pump gas/E85 and 10:1 before...but switched to NGK R5671A-7's with the E85 and higher compression. I tried the regular 3924's with the higher compression and they didn't like it at all!
Walmart 3924's and 5 gal of purple 112 and about 3 gal of 93 pump.. I wanna run VP MS109 ox fuel and NGK's but I don't know what NGK to run...?? Im at 10:1
I'd try the NGK R5671A-7's. They should do fine...I just ordered some from Jegs this morning. They're a Hot-Medium Heat Range and should work great for you. You can also get the 3924R's, which are an actual racing plug and see how you like them as well. I like the NGK's because they're easier to see the discoloration on the electrode and threads if you're reading your plugs. The Autolites have black threads and electrodes, and the NGK's don't. The 3924's and the 3924R's are actually different... I hope that helps...
Have you tried just running pump gas instead of Purple, a little more bite you might pick up some. There was some good air last weekend I almost made it up to Mason on Sunday but you know how that goes.
I ran pump 2 passes and then put in 5 gal of purple at two separate test n tunes and the car always picked up .007 to a tenth. Im still open to anything, I ran VP MP109 and liked it, but its not cheap... As for bite, the car went from a 1.59 60' to a 1.55 with the gear change so its hooking good. Just didn't see the e.t. drop like I hoped with the 60 improvement. They are 275s MT ET Radial Pro, They hook like a mother over the old version.. I know x275 cars that have moved to them and swear by them.
what size converter, and were does the converter flash? and have you tried shifting higher?, I don't know what cam you run, so I don't know where you are at power wise? shift it higher if you haven't tried it yet,also what are you running for timing. a lot of these aluminum heads with more advanced combustion chambers have found power gains dropping down to 34 and 32 degrees, try it if you haven't yet. I like the autolite racing plug, and I have always liked a colder plug and jet it for the colder plug, the autolite racing plug is natural/silver, not black so it is easy to read, and you can get them at napa. also, when you are reading the plug, read the color of the porcelain, not the metal. its not that the other advice is wrong, just my opinion Duane
I`ve always found that you want to start w/ new plugs & be on the rich side & jet down until you get that light brown on the electrode.The metal ring on the plug will show a lean condition quicker than the electrode,blast that 1/8 mile hard and hit the kill switch and coast into the pits and ck a couple of plugs.This will give you your most accurate reading.
I run a 4,600 converter and it flashes to 4,600-4,700, I picked up a set of AR3923 plugs yesterday and I run 34deg timing, I have played with timing and have seen no gains in mph or et from 32 to 36 deg so I just run 34 deg. Also the cam is a PAW SSI catalog cam. Hyd. flat tappet 351/5.0 H.O. firing order 520/544lift 224/234 dur @ .050 with a 109lsa installed @ 0. I played with shift points and consistently pick up e.t. shifting @ 7,000 over 6,600 but don't want to push my luck with a stock crank and rods running it any higher even with it having ARP hardware, studs, girdle..
