Finally broke down and bought a pump cam assortment kit. Just wondering what anyone might recommend I start with on the pump cam. The cam on it is so discolored I can't tell what it is. Safe bet that its stock since the rest of the carb is untouched. In the process of stepping up my main jets and getting ready to order the conversion for the metering block. After I pulled my heads I really took a good look at all my plugs and they are all white.....not really any color to them. Looking to richen it up a bit. Main jets were 642 so I bought a pair of 66 and 68 jets. Gonna start with the 66 and see what happens. Thanks for any help or insight guys.
Don't even bother with the 66's and start your baseline testing with the 68's. My guess is that you'll likely end up somewhere around 70 on the primary side and maybe 74-76 on the backside. Start your pump shot testing with the orange cam and increase from there. If it keep responding to larger cams?.. drop back down t the orange one and run a bigger shooter. I'd guess a 38 shooter size would work well. Also, that's a small plenum design and as I mentioned prior via PM.. an open spacer will help the fuel mixtures transition around those funky corners near the port/s roof entry. Otherwise.. a grinder will easily pick up another 3-5 horse without the spacer. A grinder AND a spacer will net closer to 8+.
I installed the 1" spacer I had laying around earlier and installed the 66 jets. After reading your post I'll step up to the 68's and verify what size PV is installed. Also gonna verify the squirter size. Will also be removing the choke assembly and cutting off the choke tower per our talk earlier. Hopefully I will get all that done this evening and take it for a spin.
this is the stubstack that I use with chopped towers. http://www.summitracing.com/parts/knn-85-0400?seid=srese1&gclid=CM7s8ZDj6L4CFfSjMgodLyIAmg
Cool. Looks like I'm building a wishlist quick. For now I'm gonna just remove the actual choke assembly. When I move next week and get settles in the new garage I will mill the tower.
be sure to plug that vacuum passage under the choke mechanism too. Look at the choke pot to see where it's located.
68 jets are in. Squirter was a 25 moved to a 32....biggest I had available. Green pump cam..noticeable difference. No bog at all......just straight wheel spin
You're obviously going in the right direction. Like I mentioned on the phone.. get yourself a straight style(no tubes) discharge nozzle in a .036 or .038 and you can easily drill it out to whatever you want. That will likely be close enough that you'll not need to attack it with a pin vise though. And don;t get too carried away with tuning the primary jet until you get some proper jets in the rear plate kit you bought. Otherwise.. you'll be chasing your tail and redoing things a bit once you have the proper size rear jet. 68-70 primary and 74-76 secondary should be pretty damned close though.
