hi everyone, I'm looking for an .4 .5sec off my ET. for now I'm at 13.1s @105 mph , 2.00 60', 8.45s @ 85mph 1/8 mile my combo is 1970 GS, 455 +030, B4B, 870cfm, headers, 3in , 2800rpm stall, 3.42, lunati "popular mechanics" cam (230-240-112 I think..). I have the stock head with a little cleanup , would stage1 heads make a difference ? what about 1972 stage1 heads ? any differences between 1970 and 1972 ? I'm running points right now ... what about a capacity discharge ignition ? would that make a difference ? any ideas ???? thanks Olivier
For stock 70 455 engines with 70 heads the difference in non stage and stage 1 heads on the Buick factory dyno was 16 horsepower.
so I don't think it will make a lot of difference, since it's an expensive upgrade, I don't know if I should go for it... any differences between '70 and '72 stage1 heads ?
You don't have a "stock" 455 and Stage One iron heads can be had fairly cheap. It will also compliment any future upgrades. Stage One heads are like a gift from God.
Probably not what you're looking for, but that 60' time could be a lot better and will get you the time you want for relatively little $$$. What is the set up now?
I might be able to get 1972 heads... but aren't they different chamber volume wise?, if I drop my compression ration , I'll be losing the benefit of the larger valves, no ?
I have drag radials now (275-50-15), I also have in stock some DOT (26x10x15) which I haven't tried yet, I don't know if that would make any difference. I know that I'm spinning of the line , so that hurts, but kind of hard to appreciate the lost on that.
Any improvements you can make in that first 60 feet (especially traction) will help a lot. I don't know where the "gift from God" comments are coming from, but the only reason I'd recommend the larger Stage 1 valves is (1) if valve lift is beyond 0.550" or (2) you need to replace the valves. A ported set of standard valve heads can easily outflow unported Stage 1 heads at lower valve lifts and port velocity can be higher. The difference between '70 and '72 combustion chambers is negligible if you're comparing heads with the larger valves or comparing heads with the small valves. The Stage 1 mod increases chamber volume a bit, I don't remember how much. Many of the heads between '70-'72 and beyond are the same castings. Devon
I mean is there a difference between 1970 stage 1 heads and 1972 stage 1 heads ? I probably should work on my 60', but here there's no glue on the track , it just a regular road (long stretch of a autocross track) , so it's hard to hook up... it seems that most of our cars are .5 - 1 sec slower compare to the US. As a point of comparaison a stock '10 camaro SS or a stock '10 srt/8 challenger are in the low 14's on stock tires, I think that's slow compare to the magazines' tests . don't you think ?
Sorry, I thought I explained that in my last paragraph. If there is a difference it's more likely due to manufacturing tolerances. Again, some '70-'72 heads share casting numbers. The same tooling design and process was used by Buick to convert the standard castings to receive the larger Stage 1 valves. Devon
sorry I didn't quite understand, the first time. I guess if ever I can get a set of heads not to expensive I'll go for it, but I maybe not my priority money wise .
Head porting. Get your small valve heads ported. That will make a HUGE difference. You can't hook up what you have now, so work on your 60'. Try lowering the tire pressure, and make sure you get them good and hot. Use an air bag in the right rear spring. I'd also buy some traction compound and treat the launch pad myself if that's what it took.:laugh:
If it is just 4 tenths or so you're looking for and you want to spend as little as possible to get it, traction and cold air intake/ ram (if you don't already have it). As Larry said. Air bag, traction/ no hop bars, air pressure and get them good and hot. If you can get your 60' even down to 1.8, you should see that as 3 tenths better at the big end. If it's more power you want, head porting is certainly the way to go. Of course, more power and traction...:3gears:
Maybe go with a tight 10 inch stall that flashes to around 3400 or so. Gears are ok. Try and run on a 28 inch tall tire.
Theres a car locally that runs 12.5 at 104mph. Its a bit stripped out, but most of the interior is there, and it hooks pretty good. You have the power, you need to focus on getting off the line.
thanks, you're all probably right, it seems that I have sufficient power for what I'm aiming. So I have to lower my 60'... I have air bags, but since I changed my rear bushings , the rear end suspension is very hard. I may have to look at those rear shocks. And I guess the driver has to practice ! no traction : it's a new problem for me !
