On my JAGUICK.... I switched to 28x10 in drag radials to run 10.00 index class (hd 28.5x11.5 slicks). My trap rpms are 6400 at 135 regardless of weather like a governor as the motor is done at that point. 800 passes on motor, about 400 on valve springs. Could put new springs in but rather not rev any higher. Yesterday was real hot and 2800 DA and it still ran 10.0s at 135. Don't want to rev it any higher. I already have 3.50 gears and a tight 8in converter (4200). Can't really do less gear as it will just make converter slip more. I guess I could go with a tighter converter but then can't cut as good a light on PRO tree. Tried a 29.5 tire once and hit front of fenders....maybe there is a 29in drag radial but I don't see any. Any ideas?
Then what is the problem? If it runs 10.00s like a stopwatch, then what are you trying to solve? If the engine has its tongue out at 6,400 then it’s the perfect governor
Afraid I'll drop a valve running at edge of valve float....hard on keepers. Plus it's a Buick motor and 6400 every pass is not in it's best interest...I want to go 1000 passes.... I guess I'll just put some fresh springs in..... In better air recently it went 9.80s but still only 135..... Drag radials don't grow like slicks....28 is 28...my 28.5 11.5 prob were 30in thru the traps. If I go back to slick my reaction times on PRO tree will suck.....
Not much of a racer here, but have some education in metallurgy + strength & elasticity of materials. The new springs idea is a good one! Seems like good insurance to me. I probably don't have to recommend checking the new springs first, guessing you'd be doing that. And, for the sake of comparison, check the old ones to see what's up after all their hard work! Devon
I shifted 6500 rpm on my first 464 every pass and never had an issue.......never changed the springs in heads and they were just TA STAGE1 PLUS. Nothing crazy, was running low 11s in a heavier car....3800 on 29x10 with 4.10. It went through the top end about 6200. As long as your balanced good, and have good oil pressure i wouldn't worry. But if you can't/dont want to change tire, gear is about your only choice. Not sure what spring your running, but if alot of lift they will get tired faster
Might just go to 28.5x10.5 slick (11.5 not allowed in 10.00) that will be .5 taller and also grow on top end. Just can't beat the radials for reaction on a PRO tree.
I’m a drag radial guy. I haven’t needed a slick in over 20 years. I’ve ran the same springs with a solid roller in one of my engines for 18 years and counting. It gets daily driven and has made countless passes. However,that particular engine is done at 5800. I run a 28” tall tire with 3.73’s and a continental “tight” 9.5” converter. If springs are your real concern,just change them after a set number of passes.
Do you have the small valve stem valves? I had 10 years of racing on my 64 in the 10.5 range before it finally broke. I was having what I also thought was valve spring issue. Actually the valve stem were pulling off the head and one let go on me in Cecil. The center of valve head actually had signs of cracking. Take time to check the valves and save the engine.
Yeah...regular TA Stage 1 valves. They may not be floating...the head flow maxes out at 5900 and so at 6400 they are done in high gear.
Your in a box Bruce... and exactly why be build Buick race motors with good aftermarket rods and block girdles.. so 6500 is no big deal. Lot of combos have to rev that high to get thru the quarter.. I know we did back when we had the Stage with 260cfm iron heads.. it was all done at 5800, but had to go to 6600 to get off the track. Out of power at 5900? you got iron heads on that thing? Finished a bracket motor last week.. Stage 2 SE pump gas deal.. my own design cam (254/264@.050)- 482 shortblock, no girdle or fill, flat tappet hyd cam with solid lifters. A new pump gas race combo I am pretty excited about. Nothing exotic here, just my $550 bowl/chamber porting, and the right carb and spacer, untouched SP-1. No problem with this motor at 6400.. Put some valve springs on it. Get your 200 passes.. and then call me, we can get you set up with the internals so you can build a motor like this, and quit worrying about breaking things. JW
Similar to my motor with S1SE heads. Max power at 5900. Motor could just be tired....lots of runs....and cooked it once by not putting water pump on and making a pass. That heat was probably hard on valve springs, right? Not to mention rings.....
Ya heat is not good for valve springs.. I was surprised at how well that one last week held on..only about 5 HP down at 6600... that one will keep on pulling, won't nose over like my old iron head motor did. JW
What I really need is a lockup converter...lock up in high gear. Jim...have you done any 350C lockups...can they be built hold up with 650hp?
