1776 with rgbs 4.12 or 3.88 tranny?

[Gil-bug]

Hi i have a 1965 split bus with rgbs and a stockish looking 1776. (Stock 4.375 tranny and big nut rgb)
Aa performance cyl. and heads
278 novak cam
123 ignition
9:1 compression ratio
37 pict 3 carb
Stock air filter and exhaust

The engine runs great and serms strong but don't know how much hp. Could anyone know approx. how much horse power this could be


With the stock 4.375 tranny, It's quite high on rpms in 4th gear. I want to be able to drive 60 mph with less rpms. and beeing able to drive some hills without effort.

Which tranny would you recommand knowing that i want to keep my big nut rgbs?

3.88? 4.125? 4th gear 0.82 or 0.89 ?

[AS350driver]

When I had my 65 Westy transaxle rebuilt, I went with 4:12 instead of 3:88
It has a fairly high performance 1776 dp. I retained the .82 4th gear.

If the bus isn’t a camper with the associated extra weight, a 3:88 and .82 is nice. I had a 64 standard microbus with 3:88 and a unusually stout 1641 in it; and loved the combo. 65 mph and still good acceleration and good in the hills.

[Lind]

A 1965 bus with a 1500 would have come with a 4.12 ring gear. You should have no problem driving 65 with a 4.12x.82x1.26 and stock sized tires. I can easily drive 65 on flat roads with no wind with my stock 1965 bus which has a 1600 engine, 4.12x.82x1.26 and stock sized tires. If you put a higher geared transmission in your bus, it will rob you of your power and put you into third gear on less steep hills.
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Idaho VW license plate frames or other dealership items.
VWoA literature and early dealership or distributor literature/pictures/information
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[pyrOman]

Run taller tires! For years I ran an 1835 with RGBs and taller tires. It did just fine. Once I installed the IRS, I had to go with smaller diameter tires.
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Some people are so busy being clever they don't have time enough to be wise.

[AS350driver]

[iamdonquixote]

with that configuration of your engine, I wouldn't bother upgrading the transmission.

if you decide to get a built transmission, get an engine to match it. what you have doesn't appear ( on paper ) to be much more than stock.

[Alan Brase]

One can certainly change a lot of things to get different performance. Displacement changes by itself changes hp hardly at all. Air flow through the engine is what make horsepower. HP is what determines your top speed and cruising speed.
I have had great fun driving a near stock 1640 engine (slip in 87's) single port.
(I also had a 1978 with about 100 hp)
The further you go from stock, the more you will have to learn from your own mistakes.
_________________
Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[Clara]

[Gil-bug]

[sled]

with your tires and transaxle gearing (assuming its all stock ratios for a late big-nut box) you're spinning around 3572 rpms at 60, and 3870 rpms at 65.

thats a bit higher rpms than I would want to be cruising. Would you entertain larger tires? this would of course lower your rpms.

if you went to a 4.12 ring and pinion, this would drop your rpms at 60 to 3365, and at 65 to 3645
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drive your split.

[srfndoc]

The exact reason I run 15" bus rims with 195R15LT tires. Overall dimension is about 27" which helps keep the rpm's down. You can use the formula in my signature to figure out your rpm's based on tire dimension/rgb/R&P/4th.
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RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches

[ted698]

I have a '67 with stock RGB's (1.26), stock gearing (.82) fitted with 205/80R14 tyres - big! - 27.2" dia - very slightly bigger than original crossplies.

Speedo is bob on according to GPS

I have a Tacho fitted and my RPM's are about 3,900 at 65 mph, around 4100 rpms at 70

I have a 1904 SP with dual Kads and a CSP Python exhaust etc - I worked out out using the handy calculations for RPM's that changing to a 4.12 R&P would drop 200rpm off, changing to a 3.88 would take about 500rpms off.

However it does drive nicely currently, with plenty of poke, just motorway/highway crusing at high speed is a bit wearing (in both senses! hahaha) - I have a friend with a early Late Bay with a 3 rib box - and I can leave him for dead pretty much anywhere, as that seems to have a fairly long 4th.

[srfndoc]

[audiman72]

[Alan Brase]

Just from memory, I kinda think the 185R14C tires used on T2's and T3's (Vanagons) from about 1970 to 1992 are all about the same height as the old 6.40 x 15 bias ply tires originally fitted since 1955. 25.5 inches or so.
Fitting taller tires will certainly bump up your final drive ratio quite a bit (lower numerical) and it is so easy to do without the major commitment of gearbox changes.
Not sure what sizes will fit, especially the non flared early rear quarters before 1963.
I'll be looking for the tallest skinny tires I can find for my 1956 single cab. Sticking with stock gearbox for now. I assume that would be 195/75 or /80? who sells them?
_________________
Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[ted698]

[Blue Baron]

[storm]

Have a’66 bus with a 2027 Scat engine. 3.88/82 4th gear, reduction gear boxes 195x70 x15 inch tires.
I had use this combo in a area of flat land. Cool running and low rpms.
Now living in an area of 6 to 10% hills. 4 th gear hardly used. Even tho my 4 gear can work sometimes head temps raises up. Going down hills temps go down to 290-325 degrees.
If I do it again would go to a 4.125 r&p or use a smaller diameter tire.
Ok for the Vw people that want to go up hill faster, my area where I live people pass me going up hills. I just put on my flashers.
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always ready to learn and give advice

[Gil-bug]

[Gil-bug]

Hi

I had a rebuild in a tranny shop. It is 3.88 now and is just great. Lower rpms and more quiet.

Gilles