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Tip for a very Hard shifting race 727 build
Posted: Sat Nov 05, 11 9:46 pm
by Les Szabo
Just thought I'd put this up for those Race 727 builds.....from experience of the '71 340 auto car I ran many moons ago.
When we did the full build on the 727 trans to manual shift, we drilled 4 1/8" holes in the toothed drum which held the clutches, this was not I believe in the instructions which we followed to the letter..but a suggestion from Mr. L. Pollen who built it and who suggested it if I wanted a hard shifting trans.
Anyhow, 1st>2nd would brake your neck and screetch the road tyres, and 2nd>3rd was almost as hard and instant....fantastic!...
If this is old news or wrong, I'm sure I will be put in my place from the experts... just thought it may help some of you budding 1/4 milers gain some edge......Les
Posted: Sat Nov 05, 11 10:02 pm
by Dave-R
It is pretty normal to drill the oil holes in the rear clutch piston retainer out to 5/32". Is that what you mean?
Most shift kits involve drilling the valve body separator plate and part of the valve body itself. Different governor plugs etc. That is usually where the firmer shifts come from I think?
Posted: Sat Nov 05, 11 10:04 pm
by Dave-R
Oh the front and rear servos probably play a part too I guess?
Posted: Sat Nov 05, 11 10:51 pm
by DaveBishop
Hi Les Mr Pollen got that trick from me and I got it from instructions in a B&M complete rebuild kit that I bought back in the mid 1970s. I remember going round to Dave Pollens house must have been about 1980 when he wanted a turbo 400 rebuilt. Its funny he wanted me to build at his house soon after that he started building gear boxes himself I remember his brother coming to my house and asking me questions on different boxes. I didn't mind as by that time I had stopped building them. Built a few again in the early 1990s for a Monster truck circus that was travelling all over the country they couldn't understand why they kept on blowing standard boxes up when they were fitted behind 500cu.in. engines just didnt want to spend the money I guess.
Posted: Sun Nov 06, 11 11:58 am
by Les Szabo
DaveBishop wrote:Hi Les Mr Pollen got that trick from me and I got it from instructions in a B&M complete rebuild kit that I bought back in the mid 1970s. I remember going round to Dave Pollens house must have been about 1980 when he wanted a turbo 400 rebuilt. Its funny he wanted me to build at his house soon after that he started building gear boxes himself I remember his brother coming to my house and asking me questions on different boxes. I didn't mind as by that time I had stopped building them. Built a few again in the early 1990s for a Monster truck circus that was travelling all over the country they couldn't understand why they kept on blowing standard boxes up when they were fitted behind 500cu.in. engines just didnt want to spend the money I guess.
Hi Dave.......oh ok, so old news then, never mind, thought it might've been, thats the trouble when your on about mods from 20+yrs ago....just thought I could help some as its such a small mod but has such a big effect and can be overlooked on a rebuild.
All the best to everyones racing efforts in the future....Les
Posted: Sun Nov 06, 11 12:06 pm
by DaveBishop
HI Les old news is good news and I glad you posted it. The problem is that things get forgotten over time. Lots of people have just got into Mopars so just keep up the good work otherwise things will get forgotten.
Posted: Sun Nov 06, 11 12:39 pm
by Les Szabo
[quote="Dave"]It is pretty normal to drill the oil holes in the rear clutch piston retainer out to 5/32". Is that what you mean?
quote]
No Dave, there's a large toothed Drum which holds the clutches, you drill in between the teeth on the outside.....not a standard thing to do on a rebuild....Dave Bishop could explain better for a more technical version, he was/is the Top Man on boxes...Les
Posted: Sun Nov 06, 11 3:26 pm
by DaveBishop
Hi Les Thanks for that endorsement. Blue has now the top man in our area for Mopar boxes has taken it to a new level.
Posted: Sun Nov 06, 11 5:08 pm
by Cannonball
Les Szabo wrote:Dave wrote:It is pretty normal to drill the oil holes in the rear clutch piston retainer out to 5/32". Is that what you mean?
quote]
No Dave, there's a large toothed Drum which holds the clutches, you drill in between the teeth on the outside.....not a standard thing to do on a rebuild....Dave Bishop could explain better for a more technical version, he was/is the Top Man on boxes...Les
its to get rid of the excess fluid trapped within the clutches for a harder/less slip apply.....
Posted: Sun Nov 06, 11 7:08 pm
by Les Szabo
Cannonball wrote:Les Szabo wrote:Dave wrote:It is pretty normal to drill the oil holes in the rear clutch piston retainer out to 5/32". Is that what you mean?
quote]
No Dave, there's a large toothed Drum which holds the clutches, you drill in between the teeth on the outside.....not a standard thing to do on a rebuild....Dave Bishop could explain better for a more technical version, he was/is the Top Man on boxes...Les
its to get rid of the excess fluid trapped within the clutches for a harder/less slip apply.....
thanks Dunc...it works!
Posted: Sun Nov 06, 11 8:26 pm
by Dave-R
Good to know.