7 " vs 8 " converter?

[danny waters sr]

First of all the car is a 66 chevy ll 4- door 283 220 hp stocker. With driver it weighs 3045. P/G with 202 low gear 28x 9 hoosier ,538 MOSER 12 bolt 4 wheel disc brakes . So far i have had my best 1/4 mile et of 12.25 @ 105.388 mph. 1.65.. 60 ft time ,4.90.. 330 ft ,7.69 1/8 mile @ 88.238 mph. This is with a 7 " converter leaving @ 4200 and shifting @ 6400. any rpm above that just don't pull. It will turn 7000 easy just no power. I had an 8 " in it and ran a 12.42 but could only leave @ 3000 and it was trying to creep then and 60 ft stayed the same as above. I guess what i am asking is would a looser 8 " be faster. It seems like the 7 " don't actually try to lock up til around the 60 ft mark. and is so sloppy loose that i am also having a hard time to find a spot on the tree. Any input would be appreciated. Thanks . If you don't want to say anything on here just pm me. I am happy for the progress i have made in 2 1/2 years as this car started out running 12.98 -13.00's.

[Lapeeracing]

I would think that the 8" converter w/45-5000 stall should help you. My experience with the 7" is that you need a LOT of rpm to make it work. Testing will be the final proof! Call Lenny @UCC-great to deal with and has worked with a lot of stockers.
good luck,Lyn

[Adger Smith]

It will run quicker with the correct 7" converter. You are just looking at the 8" Vs 7" size and not how the 2 converters are configured. You have no torque, you need the right converter to multiply what little you have. I have a known A-1 that might be close. You could test with it and then we would know where to go.

[GTX JOHN]

We run a 318/230 in N/SA. We started with a 8" that would stall about 3000. Every time we loosen the darn converter it would pick up both 60 Ft. and ET. We are on the fourth converter that goes easily to 3800 against the brake (No 2 step) and it show 4800 about 20 feet out. At 12.25 Et we only go about 102 MPH with a 1.56 .60 Ft. Bear in mind our car is 3520 LB. with a touquefite. We had no luck our selves with even a tight 7"..... was just terribly loose by 1000'. We were lucky we get a deal on converter adjustment! It is not unusual to cycle a half dozen converter changes to find out what any of our low horsepower combo's like.. Hope this helps!!! We shift around 6400 and go thru lights 6800. Just my opinion

[Mark Yacavone]

The 8" converters in Stockers, usually start out with a factory designed stator profile. Those designs most often multiply more torque due to their larger diameter, among other things .
The 7 inchers most always use a fabricated stator, which fulfills it's function to a certain extent but are usually used in a super high RPM range.
Given the lower torque curve, (dual plane manifold, small ports, valves ) of a 283 Stocker,
I would tend to favor the 8" style. That's not to say that 7 inchers haven't been used successfully in Stockers.
Sorry for not giving a definitive answer here, but I think it may depend on who you're working with.
I don't want to leave anyone else out but I think I would want to work with A-1 on a 7" in your application.

[Adger Smith]

Mark,
PM to you

[Mark Yacavone]

Originally Posted by Adger Smith

Mark,
PM to you

Thanks for the info, bud

[Glenn Hayes]

It would be great to see what Lennie from Ultimate Convertors has to say in regards to this, I would like to read about it and learn too.

[danny waters sr]

Thanks for the comments. I plan on putting the 8" in it when i get back from Fla. I will let you know what it does. I also am thinking of getting a little tighter 7". I don't really want ot send my 7" back to play with it ,. If i do that i may lose what i have got already .It just seems to me it should have at least around high 1.50's or very low 1.60's.

[Ultimate Converter Concepts]

I would tend to agree with Mark as to the 8" being faster in this particular combo. From what Danny's saying in regards to the small engine needing to be in it's torque range quickly, because of the amount of torque and where it is,the 7'' gets it there quick enough, but is not turning enough RPM to sustain lockup in the 7". A lightweight 8" piece, loose enough to get it to approx. 3-400 over peak torque ,as the PG is a little more conv. sensitive even with a 2.02 and needs a bit more to leave. Gear selection is important also as the 8" will couple better in high because it has more fluid capacity, you should be able to get away with a little more gear. With the right 8" piece and corresponding gear it should help on the leave, on the fall back which is critical on the PG and keep it locked up fairly well in high gear. After all is said and done, your combo will run it's best where the engine is operating at it's happiest, and every one is different. Hopefully this will help out a little.