I am rebuilding my sbb and need some advice on what T.C. to use. Here are my specs. SBB .030 over pistons comp 268 cam headers TA alum intake either 3:23 or 3:42 rear posi. I think it is the 3:23 but have not pulled the cover yet. just need to know what converter would work best for me. It is NOT a race car, just something to cruise with and when the opportunity presents itself, the ability to spank them "know it all" rice grinders and mustangs. OR, do I leave the stock converter in and change the rear to the peg leg 2:73 diff that i got sitting here.
Chris, You need to tell us what a comp cams 268 is, because there are various versions of it. some duration figures at .050 lift would be great. The cam description usually states a power range. If it is something like 1500-5000, the stock converter or a 2000 stall would be fine.
Chris- You have almost the same setup I do. I have been very happy with a 2200-2500 stall converter on my SBB with the 268 cam. My experience is my 350 stalls it low in that range. MY car: SBB 350 .030 over 9:1 compression Mild home-ported heads Comp 268 cam 3.42 posi rear, P255/60-15s 2.5"exhaust, flowmasters Headers (going to manifolds now cause I sold my headers to someone) I think the spec for the 268 cam is power range 1500-5500RPM. Also, I tried 3.73, 3.42 and 3.23 ratios with my setup. The motor I have liked the 3.42 ratio the best, and that is what I am sticking with. The 3.23s were the best of the three for hiway rpms and still had get-up-and-go, but the car was most responsive to the 3.42s IMO. Go POSI! You are going to like the 268 for a performance cruiser cam.
Chris, What are the specs on your cam? I see everything from 218* to 224* intake duration on the 268 comp cams when I google them.
lol...you need a good set of manifolds....I bought some headers from someone and no longer need the manifolds
I will post the cam specs tonight for you Larry. Ken, what king of rpm were you at 60 mph with your 3:23 gears? before my build the 3:23 posi was the only upgrade(bone stock engine/trans) and I was 3000-3500 rpm at 60 mph. This seemed a bit high and i didnt like driving it that high, it sounded like the pistons were going to change holes.
With 3.23s and the TH350, I seem to remember something more like 2700RPM at 65mph. Just within my comfort level. But then I am running 255/60R15 tires, not sure what you've got. The Non OD transmission is the thing. 1:1 ratio = hi rev with performance gears. I am trying out a 200R4 OD trans with my 3.42s. If I can get it to work and like it and can build it for less than my mortgage then I will keep the OD. If not then I will go back to the TH350 and really rev my SBB.
Are you sure you have 3.23's? At 60MPH with 3.23's and stock height tires (26.6"), RPM's should be more like 2500 RPM 27" tires. RPM = 336/27 X 3.23 X 65 = 2613 RPM with no slip, so 2700 sounds right on the money.
I have 255 60/15 tires on the rear. Cam @.050 duration int. 218 exh 218 lift int .3026 exh .3026 seperation 110 deg same as what Ken said in post #5
Well, unless your tach is way off, your RPM's should be as I stated. A 2000 stall converter should suit that cam just fine.
I seem to remember the 3.73s revving 3300 at 60-65 mph... I agree too many revs to be comfortable just cruising along.
thinking about it now......i changed tires since i drove the car last, I had 295 50/15 on the rear before, and havent driven with the new tires yet
I am currently building the engine to these specs Larry, the spin counter was minimum 3000 with my completely stock 350/350 setup and 295 50/15 tires. Who makes a good 2k stall converter for a bop th350 and what should i expect to spend??
Go to one of the major converter companies and get a custom built unit. There is no such thing as a 2000 stall converter. It's what it will stall at in your car. For the street, you want a converter to be relatively tight until you romp on it. You get what you pay for. 350.00 and up usually.
