How high do you spin your 4.15 or 4.25 RB stroker?

Sheer (morbid?) curiosity...

Do you build 'em to go much over 7K on the big end, even if you're shifting them below that RPM?

When we ran the B1 all out we shifted it at 8400. I am trying to finish up my 605 and expect to be shifting it around 8200 or so.

My first pump gas stroker motor 512/518 C.I. like to be shifted at or above 7000 to 7300 RPM. That motor made peak HP at 5600 RPM and peak torque at 4500 RPM on the engien dyno At the track it went fastest shifting at or above 7000 RPM, the converter, gear ratio, tire size and all the other variables do come into play

6700

My 514 dyno motor makes peak power at 7000 rpm so we shut it off fairly quickly after that. It is a 4.15 stroke with a Callies crank and 7.100 Oliver rods so I'm sure the shortblock could handle more rpm, but it just runs out of air.

It still makes 900+ hp at 7000 but if I had bigger heads on it then we could wind it out a bit more and make even more power.

The valvetrain is most likely good to something well past 7000 rpm. I have Jesel rocker arms, a Jesel belt drive, big valve springs and 1/2 inch pushrods so it would spin higher if I had more airflow.

572 shifting at 7300 trapping at 7500

4.15 stroker here. I usually spin it to around 65 at the traps, but have gone to 7 a couple times between shifts, unintentionally...

I think ET and HP numbers might play a role here too Small bore hp=RPM!!

I was gonna have to spin my B1m/c 514 to 8800-9000 to make
it efficient

My 572, make the shift at 6900 runs 7100 through the traps.
Doug

We spin our 632 in 7900 to change gears and out the back 8300. It is 4.600 bore and 4.75 stroke. we are in the process of building a 565 in motor 4.600 bore and 4.25 stroke with our new head. I think we will probably be shifting around 8500 and be around 9000 on the big end.

What block are you using to get q 4.600 bore? Assume it is the Indy 4.84" BS deal. Wish there were some decent heads for that block, like maybe a 4.84BS Predator head.

7100 shifts, 7800 in the traps with shorter tires. 4.15 stroke, Manley
H beams, 2432 bob weight.

Shift my 540 at 7200 and trap about 7600. Callie's crank and Compstar rods. Been 9.35@143. Looking for more this year.

Randy

My 496, I shift @ 6800 and cross @ 7200!

Gee, I feel like a small block guy with only a 505 stroked pump gas 440. I shift at 68 and cross the line at 67. It will easily go to 74 but I see no need to go that high.

There are a new set of heads that we have just designed. They will be production by the end of July. True mopar wedge they flow equal or better than the predator head with much better velocity. They will be available thru Best Machine Racing 248 987 6038.

So is the block Indy 4.84BS???

Yes is 4.84 wide flange Indy block. The only way to go.

Not to hijack the thread ......

Question re shift points. My combo E.T.s best when I shift into second at around 5200 (near peak torque) If I raise the shift point the car slows a couple of tenths. The engine dyno`d at peak RPM / HP @ 6900 and is a 557" RBRE Hemi . Running 14.5/32/15`s , `Glide , 4.10 Dana , 5400 stall Neil Chance conv.
Anyone?
chryco




Again not trying to hijack the thread

Generally seaking you would want to shift the motor at 3-500RM above peak HP. Since it is a powerglide car my guess is the converter is WAY wrong for the combo. What is the shift recovery rpm after the 1-2 shift? What is it when you run the RPM up higher? How much faith do you have in those dyno numberers? Ideally that car should want to be shifter at 72-7400 to see it's best ET. But you don't have a ton of gear either. If it were mine I would be looking at the converter real hard and possibly gearing.

Thanks for the response Al. Unfortunately I don`t have the R`s drop between gears , as well as the RPM at the top end. ( that playback tach would have been well worth the $$$ ). I have, through another board member extrapolated what my terminal RPM is however, and it seems way low. The other guy`s car is aprox the same weight , same cubic inch hemi , one step less Bullet Cam ,(lift and dur.) Running a glide also (stall RPM I think similar). Here`s the good part, he`s turning 6200 through the eyes with 4.30`s AND 29" tires , I`m thinking mine`s a LOT less
(5900 - 6000 ). So gearing IS definitely on the top of the list.I`m thinking a 4.56 possibly 4.88 to get things right. As far as HP , the numbers don`t jive either BUT I recently flowed my fuel system and found the main filter and line pressure was probably at fault. I probably was (although the plugs all looked OK ) running a tad lean. FIXED !
Again Thanks !
chryco