collector length ? well if you plan on running a muffler I guess that would be included in the overall length. I would say go bigger if its longer. Instead of 4" consider 5"
The fender exits...Ughhh I really don't like them, but they are the way to a real short primary tube. Again you probably want 25-30" max. If you going fender exit im assuming you going to use a Burns type real short muffler? If under car then do what I did, Cut a cheap dynomax or similar straight through, I cut 5" off each end and ...there you go instant "shorty" mufflers LOL.
On the SLR, don't be shy. Im leaving in 2nd (1.48) and 4.11 out back.
I hate to say it but the trend right now is 1.40 or less and 4.30 or more. Works well with little SLR and a lot of gear out the back to pull the car through. Those 3.73 gears are lugging the car on top, but I know you got to work with what you got. Less SLR will always help with No Prep and junk tracks. If possible consider going back to the 4.10 or 4.30 and get a valve body that will allow leaving in 2nd. This also may require a stator change in your converter. Yes the powerglide could be a good option for you. It will also dump a bunch of weight over that 727...lots of stuff to think about
Do you have any racepak or data logger ? A sportsman racepak will give you so much real world info and help you see whats going on, it will eventually pay for itself in good decisions rather than useless testing. especially with converter and gearing...
Thanks for all the input! I value everyone's help.
Fender exits are pretty much not an option at this point. I still like to drive the car occasionally. Loud is one thing...4"-5" open header mufflers out the side is a whole new level of obnoxious. I'm going to see what I can fit up close to the headers and keep everything as short as possible. Right now it's 3.5" all the way back to 2 chamber Flowmasters right in front of the rear. So it's a very loooong and small diameter collector the way it sits. Gotta be killing some power on the big end I would think.
Lenny at Ultimate told me I'm most likely driving thru the converter with 3.73's and a 29" tire and it's about as tight as he can make it. One of the reasons I knocked the tire down to 28", but still not going to make the difference back to a 4.10. Now I'm trying to stick the 28" tire....It's a vicious circle! The 2.28 1st gear did make it possible to get on the ramp a little faster than the stock 1st gear.
I have a 2nd gear leave CRT valve body but can't get a decent high gear shift. RPM drops about 300-400 from 2-3 on the sauce. Put an A&A VB back in and it's back to 700-800rpm on the 2-3. I haven't had the time to dig into that, but wanted to try 2nd gear for sure especially for zero prep stuff.
I use an LM-2 that I've added Pan vac, nitrous pressure and fuel pressure sensors to. It's no Racepak but helps see what's going on.