If you don't have "pop-ups" I doubt you will have anything over 10.5:1cr, but I could be wrong. Here is a picture of my 408 with 14:1cr Probe pistons..............and the domes are BIG. I have 4:56's in mine and back when it ran B/SM it had to run a much smaller rear tire.............I think 10.5"............now I have 13" MT's but they are still just shy of 31" tall. Although mine had a Mexican 302 block and was a Clevor............302 block with 351C heads and ProShifter top loader, the guy that orgiinally built the car said he used to leave the starting line at around 6500rpm, and I know the motor was capable of 8500rpm...........not sure what he went through the traps at but he was pretty consistantly in the 10.3's and belowin B/SM in 79/80/81. With the motor I am working on with tired valve springs and a rocker arm geometry that must have been off it went 9.801............and I run a 2 spd Powerglide with 5000 stall............and shifted at 7200rpm when I did the 9.8 run.......so I know when I get it back together it will at least do that..............but I'm not going to wring it out and play safe by short shifting somewhere around 6500.....at least that is how I had the headers mod''d....................we will see. Do you have any pictures of your pistons?
I'll take some once we put the gaskets on the motor, but they rise up to about 1 thousandth or less from the deck...not sure what brand or type but they rise pretty high...and the chambers on the heads are 60cc I think...
Not trying to revive an old thread here, but this is what the piston looks like at TDC...and the chambers on the heads are 60cc...We ended up buying a Revmax 3600-4000 stall converter...we need a shifter, trans shield, and then we're down to the cheap stuff before we have everything to have it running...
Kind of the same question only a different way...........what is the compressed height of the gasket? Have you clay'd the valve clearance with the heads on? If you have a picture that is a little less close.................it almost looks like the are domed by the picture you took.........meaning the center of the piston is taller than the edge of the piston. I would think...........just guessing that with a 60cc chamber you would be a little over 11:1.....just a guess. I really think you may find out that the 4:88 gears are going to be alittle too much and that 4:56's may be the ticket..............what cam did you pick?
We checked and there's plenty of valve clearance, the gaskets we have are .040" Cometics. The Cam we have is a Comp XE274HR (.555/.565 lift 274/282 duration) I kinda thought that about the gears too, but the tires are 31x13's and the ET streets we have are 32x14's so I think the tire size should balance it out...
id put a 4500 in it ,i can get you 1 for up to 750hp for under 400 bucks with warranty, i run rev maxx also love them have sold over 50 of them this year with no come backs at all,with a 4.88 gear and 3 speed trans a 3500 will feel like a 2000 stall ,i was running there 4500 in our street maverick 351w with stock 70 351 heads we did a best of 1.49 60 foot in 275 bf goodrich drag radials
converters You can physically take a stock converter and tweak the fins, change the stator and make it stall 4000 RPM. Is it efficient? Hardly. Stall speed aint everything! I don't know how many times I have to say it. I'm no expert on converters, but if you're looking at a serious drag racing effort, I'd be looking at a 8" CCX with around 4500, spragless. I say 4500 because it should go about 4200-4300 flash stall and on the brake with the low chip out, about 4500-ish. If any street driving is going to be done, maybe we should look at a C stator with a sprag. The C is more aggressive than the CCX but the C also isn't as efficient in a spragless setup-and can cost some MPH on the big end, but if a sprag is installed it'll freewheel when the speeds start to match between the tubine and pump--which helps MPH and reduction in heat. In a nutshell, converters are like cams. Pick one off of a list in Jegs and it'll work...but a custom-built one is going to be MUCH better, but at an expense of making the pocketbook a little lighter. Again-I ain't the expert. Leave the expertise up to the guys at like FTI, Art Carr, Bill Dowdy, and a hundred others. I like Dowdy's stuff...he knows Ford engines and transmissions quite well.
I just had my old converter loosened up just a touch when the rest of the trans was updated by Mike's Transmission in Lancaster, CA and am hoping for some better 60's times with the change in converter and headers. My best has been in the 1.4's and I'd like to see 1.2's. Now with that said, I would suggest going to someone and having a converter tailor made for your application, if you find out you just can't live with it............it can be tailored to suit your needs, kind of like a cam..................and the cost of redoing it will be less than buying a new one from Jegs's/Summitt...................although the initial cost will be more. I am certainly not an expert and run an Ultimate Vasco 2spd Powerglide behind the 408. IMHO
Let me know what you run, . No updates on my car, has kinda been put on hold until we can get my truck roadworthy, but hopefully that should be soon.
I've had great success w/ ATI and Ultimate Converter Concepts. I'm currently running an UCC converter and am very happy with it.
