The V8 Owners Forum -

I have a Dax Rush with a 3.9 RV8 and SD1 LT77 gearbox. I am in the early stages of fitting a new Ford Tremec T5 gearbox (Part N0 1352-000-251). I chose this box because of its slicker gear changing, close 1st to 4th gear ratio and very high 0.63 5th gear for economic cruising. My plan was to marry i...

Just to conclude this post I have now managed to purchase a new Tremec Ford T5 WC gear box with the 0.63 5th gear. Rossco has kindly sold me his 3.14 diff gears so I should be well future proofed for a larger engine. My task now will be to source a TVR bell housing, understand what clutch master and...

I now find that the particular gear box is out of stock. So Rossco, could I please change my mind and buy your 3.1 sierra diff gears. I have sent a PM with my email address.

Many Thanks
Allan

OOOO! interesting. The one I am looking at is a V8 Tuner kit called 'New Tremec FORD T5 World Class gearbox kit (competition)' to fit the RV8. I did intend reusing my existing AP Racing triple Green clutch and Ultra light fly wheel to save a bit of cash but from what you are saying that might not be...

The World Class T5 gear box I am considering has taller gears than my SD1 apart from 4th which both share a 1:1 ratio. The 5th gear is quite high at 0.63 which together with my existing 3.62 diff would give me 70 mph @ 2172 rpm. 4th would remain at 122 mph @ 6000 rpm. This I feel would suit my needs...

Ok thanks. Ideally I would like a tall 5th gear for cruising only (like an overdrive) and use the others for lively performance. So it looks like nearer 2000 RPM in 5th could be a realistic target for 5th. I'll see what V8tuner come up with and go from there.

Thanks Rossco. This offer is very tempting and may take you up on it. Taking into consideration all the options that need assessing when upgrading to a larger engine I have concluded that I do need a better gear box as I'm not happy with my present LT77 ponderous gear changing. I have written to V8t...

I am running a 7" Sierra cosworth LSD. Gear Ratio is 3.62:1 with 120 Nm viscous LSD.

Apologies Side car, yes you did say that standard jest would need modifying. I made a tentative enquiry into having my diff gears changed. Apparently new 3.1 gears are now hard to come by. A 3.3 would save me 250 rpm @ 70 mph and 225 x 40 x17 rear wheels and tyres another another 150. I first though...

Cam gear reset to standard timing and now back on the road. Confirmed that 70 mph equates to 2800 RPM. Side Car, are the 61/55 jets you suggested an off the shelf item? Do you know of a uk supplier who might hold a comprehensive stock of Edelbrock metering rods? Tom (Super V8). Many thanks for the s...

Good point. Unfortunately I just had the diff completely refurbished last year including new gears. An opportunity missed perhaps. I believe the viscous LSD diff was originally from a Sierra Cosworth which would fall in line with your assessment. It does however make for a very lively car even at 70...

Many thanks for working out the % rod / jet settings and will test out your suggestion below if no joy from my cam timing investigation. (Your current setup (83 -65/57) is 15% and 22% leaner than base, you need to be even leaner than 22% on the power step. 80 - 61/55 is 15% 28% 80 - 61/57 is 15% 32% )

I am half way through dismantling the front of the car at present to get at the timing cover. I just want to check that I haven't done something stupid like a tooth out. I will reassemble with '0' (factory setting) on the timing sprocket. It does seem strange that my carb settings are so weak yet ru...

Ooops correction! The triangle timing mark is Advanced for higher rev HP.

Thanks for the very comprehensive advice. So as suggested I inhibited the secondary throttle bodies and went for a test run. Cruise vacuum was approx. 12”hg with an AFR between 14.5 and 15.5. I’m happy with that and assume Vac is within expected parameters? With a reasonable brisk acceleration vacuu...