512 Stroker Auto V.S. 4 Speed Trans

[MelroseMopar]

I am looking for input on what the differences everybody feels need to be for a 512 stroker motor built for a auto trans or a 4 speed car. Things I know, I am building a 512 stroker for a 69 Superbee with a 4 speed 8 3/4 and 3:55s 28 inch tires. I am going with the Holley sniper EFI Thinking Dual Quad's on Edelbrock low rise RPM intake (Duals mainly for the look. Not sure yet.) TTI 2 Inch headers in to 3 inch full length exhaust with 2 chamber flowmasters have the Hemi 833 4 speed. I think my main difference is going to be cam but am stuck there. There will be No strip time no slicks. Strictly cruze with pulls thru rpm range. I know that it comes down to cam, is there that much difference between cam selection for Stick Vs Auto?.. TKS in advance...

 

[andyf]

For street driving you'll need a smaller cam with a four speed or else the car will buck driving at low speeds in a parking lot or while cruising. An automatic has a little slip in the converter so the cam can be just a bit larger without causing low speed driving issues. I had a 512 in my Coronet with a 5 speed manual transmission. It had a 246/246 duration hyd roller and the car pulled hard once it was above 1500 rpm, but it was difficult to drive at low speeds. I eventually pulled the engine out of the Coronet and put it in my Duster with a high stall converter. Now it is super easy to drive around town. So same engine with the same cam was no fun with a 5 speed but super fun with a high stall converter. Buyer beware. If you talk to a cam grinder about your engine make sure you tell them how you want to drive the car. If you want excellent low speed manners you have to insist on a smaller cam. Otherwise they'll always try to sell you a big cam.

 

[Xp29h]

I built 512 with auto 727 with 4:10 in 8 3/4 489 case. No issues at low end or anywhere throughout..I also used this particular cam.. comp cams 571..no Eli straight carb and msd

http://store.440source.com/Comp-Cams-Custom-Hydraulic-Roller-Retrofit-Cam-571/productinfo/145-1714/

I’m sure there are other factors besides these that will go into your build that will have an effect. Good luck and have fun with it!

 

[91r/t]

I have a 500" stroker (440 block) and a 4 speed in my Charger and I love it. Only time I get bucking is in the parking lots at very slow speed but I can deal with that. That is more because I switched the gears up to a 3.55 ratio from 3.91's. When I had the 3.91's in it, I didn't get much bucking at all. My cam is a .539 lift 244 duration @ .050 and a 110 LSA. Motor makes tons of steam right off the bat and winds up faster than ****! I have no issues with a bigger cam and low end with the stick......the only issues I have is the vacuum for power brakes being around 11" which works but not great for repeat braking and then there is the TRACTION issue hahah! Car will blow the tires off of it until 45-50 MPH with the 3.91's and with the 3.55's is does it pretty good but is more thruway driveable. By the way....I have 28" rear tires as well....pretty much the same combo as you minus the hemi 4 speed which is so close to the 23 spline gear wise it won't matter. If I was to do it again, I might try a 112 or 114 LSA for a little more vacuum for my power brakes, but I use the vacuum canister for the headlights on the Charger for a vacuum storage tank that is linked in with my power booster tank for extra braking when needed.

 

[451Mopar]

First, check the crank is finished for the pilot bearing. Mine just had a rough cut hole that was too small for the pilot bearing.
You did not mention heads or pistons, so not sure what the compression ratio will be.
What sort of power are you expecting? If this is just something around 500-550 HP or more.

My 505 has the 4.25" stroke kit with the 17cc dish pistons and ported stealth heads. I think around 10.3:1 compression?
I used the Comp hydraulic roller XR286HR-10 236/242 @ 0.050", and 1.6:1 HS Rocker arms.
Torque is really good, and pulls nice to 6,000 RPM.
For the exhaust, I just used the TTI 1-7/8" headers and 2-1/2" exhaust with Walker Quiet Flow mufflers because I wanted a quiet exhaust, and don't care if I give up some HP.
I originally ran the engine in front of the 833 4-speed, and used the RPM intake and Holley carb.
Now the car has a 5-speed manual (LGT SS-700) and the Edelbrock XT TPI style EFI, but with fast 2.0 electronics.

 

[dvw]

It all hinges on cam duration. My 360 Challenger is 9-1. [email protected] .550" hyd roller with true 9.0 comp. Never bucks with 3.55 and a close ratio 2.44 1st gear 833. Its been 12.70@109 in full street trim on 87 octane.
Doug