Murray's 1951 Split Sunroof --->The Whore

ScottyG · **Posted:** Mon Jan 12, 2015 5:09 pm

murray7010 wrote:

Id be afraid to have my rpms that high on the highway for long stretches!!@

Don't be scared, Murray... 3750 in mine is a little over 80.... I've done long stretches at that fast and faster many times. I'm talking a couple of hours... fill up... repeat, repeat. If you have plenty of oil capacity and cooling, then these motors can definitely take it.

The 3.88 with an 0.82 may be turning the fan pretty slow at 60mph... you'll be running engine rpm's in the neighborhoood of 2500 or less.

mk-Zero · **Posted:** Mon Jan 12, 2015 5:27 pm

With a 3.88 i think you'd want a .89, not a .82.

murray7010 · **Posted:** Mon Jan 12, 2015 6:15 pm

mk-Zero wrote:

With a 3.88 i think you'd want a .89, not a .82.

Yeah, the .89 is the norm but i just wonder how much of a stretch it is to do a .82 in the combo. I tempted to try it

Redjames · **Posted:** Tue Jan 13, 2015 9:40 am

murray7010 wrote:

mk-Zero wrote:

With a 3.88 i think you'd want a .89, not a .82.

Yeah, the .89 is the norm but i just wonder how much of a stretch it is to do a .82 in the combo. I tempted to try it

Better get 4.88 and .95! :thumbs:

mk-Zero · **Posted:** Tue Jan 13, 2015 9:56 am

Another thing to consider though is what the rpm drop will be between 3rd and 4th. you don't necessarily want to have to rev it to 6k rpm's in 3rd every time you want to shift into 4th. What 3rd are you running, I can plot it out for you?

tommiebsmith · **Posted:** Tue Jan 13, 2015 2:00 pm

mk-Zero wrote:

I'm running a 3.88 and a 1.04 4th, doing just shy of 3750 rpm at 65 mph on the freeway. I'm deaf for 30 minutes after I get where I'm going

I can only imagine Brian's ride with the bullet (I think is what it is called) muffler.. humming over 4k down the road..

:wow:

kostya.lyt · **Posted:** Tue Jan 13, 2015 2:06 pm

mk-Zero wrote:

Another thing to consider though is what the rpm drop will be between 3rd and 4th. you don't necessarily want to have to rev it to 6k rpm's in 3rd every time you want to shift into 4th. What 3rd are you running, I can plot it out for you?

Agreed. I'm doing a 3.88 with stock 1st-4th next time around.

murray7010 · **Posted:** Wed Jan 14, 2015 8:06 am

mk-Zero wrote:

Another thing to consider though is what the rpm drop will be between 3rd and 4th. you don't necessarily want to have to rev it to 6k rpm's in 3rd every time you want to shift into 4th. What 3rd are you running, I can plot it out for you?

I was planning to do all stock gearing, just upgraded gears.

mk-Zero · **Posted:** Wed Jan 14, 2015 9:57 am

If you're going to run stock 3rd maybe a 0.82 4th wouldn't be that bad. The down side though is your car won't be very quick with that tall 3rd and 4th

Here's your RPM vs road speed with stock gears and a 3.88 R&P (for your car I assumed a 25" tall rear tire):

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Here is is same as above but with a 0.82 4th:

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And for reference, here's mine (I run a 24" rear tire):

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kostya.lyt · **Posted:** Wed Jan 14, 2015 10:08 am

I think Murray is running a tall tire, 205/70, making it just over 26" tall.

Murray's 1951 Split Sunroof --->The Whore

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