What revs to you run in 4th at 60 mph?

With the 388 trannies that you guys have and the average wheel size of 185/60-65/15, what kind of highway rpms can one expect for a 4 speed tranny in 4th?

I usually see 3200-4000 in fourth...sometimes higher if'n a crazed soccer mom in an SUV is approaching my behind...

Garth I see about 3000rpm at 60mph and 4000rpm at 80mph hope this helps.
DS.

Dave,

It's snowing here or I would go out and get you an RPM (flat road, light wind). Right now I think it might take 2500-3000 RPMs to scoot it up the drive in the snow and ice!

My best recollection is that under ideal conditions my 3:88 with Flyer 4th runs 32-3400 at 70 mph, roughly 3500 at 75 and 4000 at 80-85 mph. So a guesstimate is maybe 29-3100 at 60 mph... ?

If I remember the 3000 mark is about what I run at 60 MPH. I do know that John Steel said that the optimum cooling spped is about 3200 and that is a tad over 60mph, maybe 63 0r 64 on my speedo, I have the 3.88 with a 1776. Looks likw we are all pretty much in the same ballpark.

I was wondering myself what tbe prudent redline is on a Vintage Speedster "stock" 1776 motor is. I usually do not go above 3200 rpm. I suppose it's all relative to how thick you wallet is, but does anyone have any experienc or knowlege. Any input would be appreciated.

Now that you're all dicussing this; how many rpm's would that be with a 4:12 ratio? Thanks to all...

Dan,

Love that Meisen blue Speedster. That is the color I wanted but wife won, so mine is the signal/Guards red. What color is your interior? Great looking set of wheels!

Bruce

Quote: I was wondering myself what tbe prudent redline is on a Vintage Speedster "stock" 1776 motor is. I usually do not go above 3200 rpm. I suppose it's all relative to how thick you wallet is, but does anyone have any experienc or knowlege. Any input would be appreciated.

I didn't take mine above 4,500 rpms. Ask Jim Ward what can happen if you push it too hard. Engine quality is spotty in the Mexican crate motors, so if you have a bad one, look out. Fortunately, it seems that the failures happen early in the car's life, probably when the car is still under warranty, and I hear that Kirk steps up to the plate when one of them goes bad.

Does a 'stock' 1776 have a counter weighted crank? If it does you can rev it to 6000, but there is no point. My 1776, with a counter weighted crank, ran out of power just after 5000 (with an Engle 110 cam). If you're running a stock, (noncounter weighted) crank I would think around 4500 is tops.
Ron

The crates do not have counterweighted cranks... also, everything is cast, including the cam gear that spun off mine at 4,000 RPMs and slowing with only 2500 easy miles resulting in one massive mess of internals. They do (or did) honor the warranties though. I took the cash and put it together with the a/c I sold and some play money and built a 1776 to last, starting with a new case and good parts. (see registry)

My Speedo is cross checked by our Acura and an OHP Radar. The 3:88 and the tall 4th gear make it an easy cruiser on the highways. I haul the pikes at 75-80 on 1 1/2 hour runs... no heat problems either.
I think John H. hit it though... if it (the crate) stays together for the first year and you don't plan on anything over 37-4000 RPM that crate motor may just keep on, keepin on!

I also agree that 5000 RPM on my built 1776 is as far as I care to take it... actually I rarely go past 4500 on shifts, more often 35-4000. Never bog under 2,000-2200... I baby it while I abuse it now and then.

My next engine will be a 2007 or 2110 stroker. Maybe by late summer if I stop driving it enough to do it right. I'm using this 1776 to head west for our meeting in April first though...

Jim

Same question but with a 3.44.1 trans that IM puts in its cars with the 2110cc engines

Ricardo, I think most of our speedo's are off a little. My car does 60 at 3200, 65 at 3600, 70 at 4000 and I run a 4;12. Eddie

Jim, our cars are very close in almost all aspects. It's funny because I'm also going to build a 2110 soon. At first I thought of a 2276, but wasn't sure about long range reliability, then maybe a 2160, but thats a long stroke for for the bore size. So maybe a healthy 2110 will be the combo. Let me know your thoughts on same. Eddie

Paul need the Ring and Pinion ratio, Gear Ratio and tire diameter to get an accurate rpm at 60

example: I have a final drive ratio of 4.125, a top gear of 0.82 and 185/65 x 15 tires, for a diameter of 24.4

rpm = 60 x 0.82 x 4.125 x 336 then divide by 24.4

at 60 mph my motor is turning 2800 rpm, and at 70 it's turning 3200.
I wouldn't use this combo on a smaller motor, but my 2110 has lots of torque, so if I have to pass at 65 and don't have to gear down.

Ron

Eddie, the most important decision you have to make is what heads you'll run. I decided to go with the smaller valved head (CB 044) and a very good porting job. I'm not sure that a big valve head is the way to go with 90.5s. Also, I like to see some 'meat' left around the guide bosses (something that the CNC big valve heads from CB don't have).
Ron

Thanks for your reply Eddie. Do you know what's weird? Back in the early '80's I had a real nice '69 Karmann Ghia with the stock 1500cc engine and trans (I think it was a 4:12) and it was able to go over the 90 mph on the speedo (in fact, the needle would go back to 0 sometimes). If the rpms you reported are accurate, I'd hate to know how many rpms the engine in my KG was doing (unless the speedo was malfunctioning). Never had a problem with the engine or blew anything up (of course, it had perfect and meticulous maintenance). Just a curious thought.

Ron, you're right. The heads I'm considering using are the same heads that I have on my 1776, which are 40x35.5, that have a very good port & polish, solid shaft rockers, good adjusters, and single high rev springs. The cam is still a question mark, my builder likes the Engle 130, but the Web cams are very popular too. The 121/125 seems interesting also.

Ricardo, as I mentioned my speedo is off about 5 mph I think. The speed I listed in my post is not the corrected speed, but the indicated speed. Eddie

Bruce,

Thanks for the complement. I have yet to see another meissen blue replica. The interior is black. Tan would probable be better looking however tan tops and interiors are hard to keep clean.

Happy Holidays,

Dan

Dan,

I wish to echo Bruce's compliment. Your car color combination is awesome. My sweet bride wants red like Bruce's did, but I think this is a battle I have won. I am strongly leaning towards having your combo on my new Cabrio. Great looks! Happy holidays to you also.
Gud Yule!
John H.