how fast can you go on stock heads in a skylark? motor is 69 430 got all the bolt on stuff cam manifold headers when I say stock I'm talking small valve heads regular valve job no port work. heres the specs I got the motor free from a demolition derby guy threw it together with parts from my old motor so I'd have a fun summer driver cam 531int 560ex 304int dur 312ex dur offy single plane (1 4bbl style) 1 7\8 headers msd 6al w hei ignition built up q jet 850cfm th350 3500stall 373 gears I can't seem to make it to the track on a nice day and dyno time isn't free just looking for a guestimate really thanks
I am probably the furthest from an engine expert as anyone could be..... but that cam seems WAY TOO BIG for stock heads (springs) and pistons. I would think that: 1 - Your stock valve springs will never work with that cam 2 - You may have piston to valve clearence problems Is this engine put together already? Have you fired it up yet? o No: Hopefully someone smarter than me will chime in soon. :gt: :beer
ok not bone stock heads I replaced the valve springs and lifters with the ones that came with the cam kit. the car runs awesome. acording to crower tech dept it'll run with an un modified bottom end. I'm just trying get a rough HP or MPH/ET idea cause it always seems to be raining when I have time to go racing.
Rick, what rpm do you rev the engine too? I ask because the stock rocker shaft (when using stronger springs) could/will crack when rpm levels go past 5800 rpm's or so. They usually crack at the end where the last bolt goes through the shaft.
nobody even has a guess? I may make it to the track friday if I can get out of work early and it doesn't rain.. I'll post results if I get to go.
I'll guess I'm not sure if you'll get it to hook up. Depending on rear suspension condition/tire choice I'd say mid to low 12's. So 12.30 at 110 (if everything is sorted out) is my guess.
that would be awesome I've got drag radials and ladders in the back and a set of wrinkle slicks if I can find some more wheels
Dave, Glad you got your car together with a big block. How's the car running? Sounds like it's a bear to drive. That's a big cam you got in there. Anyway, if you can get the car to hook, then you'll be in the mid 12s as Craig and John said. Let us know what happens. Good luck and have fun...... Are you going to the Norwalk test-n-tune on July 31st? Lon
I'm going to try and hit NTR on friday If I cab talk my friend out of his trailer (in case the car breaks) I might go too norwalk its supposed to be a better track.
I run the stock heads, untouched small valve, works fine, just have to build the motor for low end torque. I use the #413 cam,performer,q-jet,headers,full 2 1/2" exhaust, TH400 w/2600JW stall, 3.55 gears, its a low compression also about 9.4/1. motor will rev but stops pullin about 5400rpm's........ Big thing is getting hooked up......thats where you time will be.....
well on a 1.90 60' I went 13.70's all day at 95 mph the car felt like it was hitting a wall at like 4500 rpm. I think my electric fuel pump is starting to go. I checked the fuel pressure before I left and it was 6psi after driving to the track it had droped to 3psi I let the fuel pump cool off at home and walla right back to 6psi and the car felt stronger. so new pump on the way this week. if that doesn't fix it I may run a bigger carb if I can borrow one to try it. while I'm at it I'm running about 14 degree initial timing with about 34 total by 3500 rpm should the timing come in later with the converter I'm using. went through the traps at maybe 4800 rpm with a 28" tire would going to a 26" tall tire drop the et with more rpm in the traps TIA
Yes sounds like you may have a fuel problem, i would try a bit more initial timing(about 18deg)with same total. I would bring the timing in about 2500. I think the shorter tires will help as well. Keep us posted Also on the fuel subject, make sure and run the float as high as posible, Q-jets hold very little fuel in the bowl. What were you shifting at out of first gear..???
Valve springs Dave - Didn't see if you mentioned it, but it's possible your springs are not keeping up with the cam. They'd have to be pretty worn out to float at 4500, but "hitting a wall" is what valve float feels like. You will need some stout springs to get that cam to rev.
shifting at 6000 rpm hit a wall is probably too strong. slowed down maybe? the springs came with the cam kit so they should be ok. I don't know how long springs last going 6 grand on a regular basis. the pump should be in mid week I'll double check the float too I set it pretty high when I built the carb. thanks for all the help keep the ideas coming.
I'm going back to the track this friday 8/1 hopefully. the car feels stronger with the new pump on the street, but I also put 26" tall tires on at the same time (bias ply dot drag tires, had 28" tall drag radials") don't think I'll get a full second out of a fuel pump but if it was real bad I might.
took the motor apart for winter and there was no windage tray in ito No: . I just dropped the motor in the car and never pulled the pan so thats my fault. Can not having a windage tray slow the car down alot? we'll see what happens next spring I guess.
Did you run a cylinder leak down or compression test before you took it apart.What condition was the bearings in,the windage tray could cause some loss but not that much for a mid manner engine.
b4551971..Just ran across this post. A few years I ran a 68 Skylark with a stock 9 to 1 short block with stock Stage I heads, no porting and it went a best of 11.40's and 1.48 60' . This was a 3500# + car with mufflers and DOT tires. I was using the KB MAXI 3 cam and a Wildcat intake, also the KB valve springs. After running the car for several years I learned that it went faster by shifting it a 5000 even though it would rev to 6500. I was running a 4.10 gear and a 30" tire. I think the heads being stock cause it to go faster by shifting it early. I ran it for 5 years and that was 3 years ago and they are still running it and has not been freshened. Jim N.
