454. Is 3,000 RPM cruise so bad? - Chevelle Tech
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post #1 of 47 (permalink) Old May 18th, 19, 4:00 PM Thread Starter
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454. Is 3,000 RPM cruise so bad?

Longish intro, but the question is at the end:

'68 El Camino SS. When I bought it about a year ago it had a very weak and worn 396, a rebuilt, but of unknown quality TH350, and a nicely built 12-bolt with 3.73 gears and an Eaton posi. My "plan" was to replace the engine with something more stout, then replace the transmission with something with an overdrive. I figured I'd make any decision regarding rear gears once I got familiar with the engine and transmission.

Fast forward to now: I have a mild Vortecpro 467 peaking at 581 Lbs.Ft. of torque at 4,200 RPM and 553 HP at 5,400 RPM. The TH350 seems to have been built well enough to live behind this engine, although my mental jury is still deliberating its future. But something needs to happen, as the extremely tight torque converter is really holding back the engine. If I set my idle at 1,200 RPM just dropping the car into gear knocks it down to 800 RPM. The braking stall is somewhere in the 1,500 to 1,800 RPM range.

With my 28.5" tall rear tires my car cruises at 2,500 RPM at 57 MPH, 3,000 RPM at 68 MPH, and 3,300 RPM at 75 MPH.. This car is an around-town toy and the engine runs so smoothly that I'm rethinking the need for an overdrive or a re-gear. Even if I do make a road trip, I'm suddenly thinking that 3K RPM may not be such a big deal.

So now though, if I keep the 3-speed, I definitely need to install a better torque converter. I think the engine would perform best with something in the 3,500 RPM stall range, but with the 3.73 gears, I think I'd burn up any converter with a stall over 2,500 RPM with normal highway cruising.

Certainly if I keep the 3-speed I'll be on the phone with a few converter manufacturers before I make any decision.

So after that long story, what are the thoughts here regarding just keeping the 3-speed transmission and the 3.73 gears and letting the car highway-cruise at the 2,500 to 3,300 RPM range? Swapping in a 200-4R would drop my highway cruising range down to the 1,700 to 2,200 RPM range. I'm now wondering if that would end up being too low for this engine. I'm not concerned with fuel mileage as much as I am with keeping this car fun, but reliable.

Thoughts?

Thank you,
Tom.
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post #2 of 47 (permalink) Old May 18th, 19, 4:14 PM
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Re: 454. Is 3,000 RPM cruise so bad?

With my 489 th 400 3000 in stall and 3.73 it was marginal on higways on longer trips so changed to 3.31 and I can live with it. 28Ē tall tires.

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post #3 of 47 (permalink) Old May 18th, 19, 4:26 PM
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Re: 454. Is 3,000 RPM cruise so bad?

I'd change the rear end to 3:08 and enjoy. I have a stockish 454 with th400 and 2:73. I love it!! Having all that brute torque right at your finger tips in a hilly area is just so much fun! I would gladly gave up a rumpty rump cam for that.
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post #4 of 47 (permalink) Old May 18th, 19, 4:33 PM
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Re: 454. Is 3,000 RPM cruise so bad?

Donít buy an off the shelf converter without speaking to the companyís tech personnel or Mark Jones. A good converter manufacturer can tailor a converter to your driving style and needs, the problem is the converter you are looking for is probably going to be expensive, but itís worth it innthe long run. Several friends that bracket race their street cars on a weekly and live 50+ miles from the track have had converters built specifically for their combination. Their cars picked up ET and MPH from the off the shelf higher stall speed converters they were previously using, and as a bonus got better mileage.

Good luck with your selection.

Steve R
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post #5 of 47 (permalink) Old May 18th, 19, 5:05 PM
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Eric
 
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Re: 454. Is 3,000 RPM cruise so bad?

To answer your title question, no 3k rpm is not bad but if your unsure give Mark a call.

Your just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
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post #6 of 47 (permalink) Old May 18th, 19, 5:19 PM
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Re: 454. Is 3,000 RPM cruise so bad?

Absolutely nothing wrong with cruising the highways at 3000 RPM or even more it hurts nothing and it actually is quite easy on the bearings.
You let an engine lug around at 1700rpm it is hard on bearings and does not oil near as well. "splash oil"

I have driven hundreds of thousands of miles at 3000 to 4500rpm in many cars.
Look at boats.
5000 rpm or more buzzing across the lake.

If the cooling system is up to snuff you should have zero issues.

Get a good transmission cooler and enjoy the drives.


Some mufflers are loud at that speed and will make you crazy others are very quiet and does not really seem to be all that much RPM when it is quiet.

My cruise RPM to the track 50+ miles away was 3800 RPM at 68 MPH with my 4.56 gears and Coan 4500 stall.
3.70 or 3.73 would be almost like an overdrive

My Coan has less slip at 6500+ rpm than a 12" 2000 stall Dacco I have.

R's will not hurt a thing ..get a converter and enjoy.
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post #7 of 47 (permalink) Old May 18th, 19, 8:47 PM
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Re: 454. Is 3,000 RPM cruise so bad?

Quote:
Originally Posted by any4xx View Post
Longish intro, but the question is at the end:

'68 El Camino SS. When I bought it about a year ago it had a very weak and worn 396, a rebuilt, but of unknown quality TH350, and a nicely built 12-bolt with 3.73 gears and an Eaton posi. My "plan" was to replace the engine with something more stout, then replace the transmission with something with an overdrive. I figured I'd make any decision regarding rear gears once I got familiar with the engine and transmission.

Fast forward to now: I have a mild Vortecpro 467 peaking at 581 Lbs.Ft. of torque at 4,200 RPM and 553 HP at 5,400 RPM. The TH350 seems to have been built well enough to live behind this engine, although my mental jury is still deliberating its future. But something needs to happen, as the extremely tight torque converter is really holding back the engine. If I set my idle at 1,200 RPM just dropping the car into gear knocks it down to 800 RPM. The braking stall is somewhere in the 1,500 to 1,800 RPM range.

With my 28.5" tall rear tires my car cruises at 2,500 RPM at 57 MPH, 3,000 RPM at 68 MPH, and 3,300 RPM at 75 MPH.. This car is an around-town toy and the engine runs so smoothly that I'm rethinking the need for an overdrive or a re-gear. Even if I do make a road trip, I'm suddenly thinking that 3K RPM may not be such a big deal.

So now though, if I keep the 3-speed, I definitely need to install a better torque converter. I think the engine would perform best with something in the 3,500 RPM stall range, but with the 3.73 gears, I think I'd burn up any converter with a stall over 2,500 RPM with normal highway cruising.

Certainly if I keep the 3-speed I'll be on the phone with a few converter manufacturers before I make any decision.

So after that long story, what are the thoughts here regarding just keeping the 3-speed transmission and the 3.73 gears and letting the car highway-cruise at the 2,500 to 3,300 RPM range? Swapping in a 200-4R would drop my highway cruising range down to the 1,700 to 2,200 RPM range. I'm now wondering if that would end up being too low for this engine. I'm not concerned with fuel mileage as much as I am with keeping this car fun, but reliable.

Thoughts?

Thank you,
Tom.
Was this a Peanut Port engine of Mark's or an oval port engine?
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post #8 of 47 (permalink) Old May 18th, 19, 9:00 PM
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Re: 454. Is 3,000 RPM cruise so bad?

Tom,
I dont think there will be a problem as far as the engine goes. There are 502 Marine engines that run at 4500 rpm for hours at a time.

The biggest issue is if you can stand it My 71 has 3.73 gears and it has made the trip from Washington DC to Boston probably 75 times back in the day but I was a lot younger then and could stand the noise. Dont know if I would want to regularly do those trips now but around town and local would be great. My car is a small block so that makes a difference too.
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post #9 of 47 (permalink) Old May 18th, 19, 10:53 PM Thread Starter
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Re: 454. Is 3,000 RPM cruise so bad?

Quote:
Originally Posted by 68Chevele View Post
Was this a Peanut Port engine of Mark's or an oval port engine?
Peanut. You know: the wimpy little low-power heads...
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post #10 of 47 (permalink) Old May 18th, 19, 11:01 PM
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Re: 454. Is 3,000 RPM cruise so bad?

Quote:
Originally Posted by any4xx View Post
Peanut. You know: the wimpy little low-power heads...
I do know, I have a peanut port head in my car now and a second one on the way. Mark makes some good stuff and a lot of power.
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post #11 of 47 (permalink) Old May 18th, 19, 11:07 PM Thread Starter
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Re: 454. Is 3,000 RPM cruise so bad?

Quote:
Originally Posted by 68Chevele View Post
I do know, I have a peanut port head in my car now and a second one on the way. Mark makes some good stuff and a lot of power.
No kidding. At first I was a bit disappointed with the power. Then I put the right carburetor on it and it really came alive. I can hardly wait to get a properly matched torque converter behind it to see what it can really do.
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post #12 of 47 (permalink) Old May 19th, 19, 7:32 AM
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I second the 3.08's. Always liked the three speed autos and 3.08's. A 200-4R would be nice too but $$$. Do you need a 1000 RPM idle?
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post #13 of 47 (permalink) Old May 19th, 19, 7:45 AM Thread Starter
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Re: 454. Is 3,000 RPM cruise so bad?

Quote:
Originally Posted by 6426yy View Post
I second the 3.08's. Always liked the three speed autos and 3.08's. A 200-4R would be nice too but $$$. Do you need a 1000 RPM idle?
Preferred idle is right around 800 RPM. I only have it set at 1,200 because the torque converter is so tight that putting it in gear at anything less will kill the engine. Yes, itís that tight. And Iíve also contemplated the 3.08 gearset, but the 3.73ís add to the entertainment and Iím now inclined to stick with them as long as Iím not hurting my engine. And by all accounts it seems like the engine will be just fine with them.
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post #14 of 47 (permalink) Old May 19th, 19, 7:57 AM
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Eric
 
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Re: 454. Is 3,000 RPM cruise so bad?

Contact a reputable torque convertor company. When I built my 71 Chevelle, I contacted Coan convertors and they suggested a convertor for me based on my gearing, engine displacement, cam specs and cylinder heads. I'm not saying Coan is the only one able to do this, but talk to a reputable company before making a purchase/ decision.
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post #15 of 47 (permalink) Old May 19th, 19, 8:47 AM
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Re: 454. Is 3,000 RPM cruise so bad?

I have a mild 454 with 063 heads & crane/summit 282HO cam, T400 from the RV & 3.73 gears, with the RV conv. it was a circus act to keep the car from stalling, I put a Hughes street rod 2000-2200 in it and NO change so I called Mike at Freakshow conv. and told him what I had and intended use he said a 3200 stall is what I needed I then said my wife will be driving this and I don't want her doing hole shots every time she leaves a stop light, anyway a week or 2 later it arrived at my door and it made the car driveable and a LOT more fun, not pushing Freakshow or anything but you really need to either ask Mark his opinion on whos to buy and what stall speed or call a convertor company then enjoy that badass engine

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