jyna06gt

looking at getting a 5.1 rotating kit from coast high performance and getting my stock block machined. Im not going for huge out of this world numbers just 550-600whp. I havent figured which type of FI i want to do but def. going FI. has anyone that had there blocks machined or know someone that has that could give me a roundabout price?

also my car is a 5 speed now, i want to change to a auto for the track when i take it. the car is gonna be mostly street car show and so on but i want to track it about 5 times next year. I was thinking the 5r55s just so i wouldnt have to get a driveshaft made but ive heard there not the best and i would have to get another computer to run it. I was told to look at the 4R70W instead and install a manual valve body so i wouldnt need to run a computer(im fine with shifting gears in a auto i did it with a big block fox body) is this true and has anyone done this? the only other issues i could think of would be cross memeber, and the center console. i would like not to have to cut up the interior but i guess if i could do it "tastefully" im down.

any help would be great thanks!

Diabolical!

4r70w is the best bet for a track car, but if it's going to see much street time I'd stay away from the manual valve body and stick with fully auto (it can be done both ways in our cars). Not that it isn't easy to manually shift an auto on the street, but it's harder on the tranny, especially a built tranny. If it were a 99% track car, I'd say go manual valve body. As for the cost of machine work, it varies greatly but expect it to cost 2k at the VERY least and anywhere up to $4k (and that's just for the machine work). What's more important is finding a good ENGINE machinist to do the work. There are lots of good machinists out there that can't get a block right to save their lives.

Also, in my experience, thinkin of strokin usually leads to strokin.

jyna06gt

Can the 5r55s handle 600-650 an stay together? I was going to get PA performance to machine it for me. They deal strictly with mustangs I was just asking on here before I called them up to bother them. I think if it's going to be that much I might just buy a short block from chp instead. Yea I've had motors stroked but they were 351, 460's this would be my first modular.

loaded6shooter

found this out in 6th grade lol

Old Mustanger

After stroking, it would be a good idea to lower your redline proportionally due to the higher piston speeds you will be seeing. Will you be running forged pistons? It would be recommended.

908ssp

Stroking is waste of money if you're going with a blower it helps a bit with a turbo. Getting forged parts is worth while for power over 500. But stroking won't get you more anything like a bit more boost so compare the cost of the added stroke.

scott4.6

I dont think stroking will increase your piston speed.

908ssp

Absolutely it increases piston speed in relation to rpm. For any given rpm the piston has to travel farther therefore it has to travel faster.

scott4.6

How does it travel farther? All that happens is they just move the wrist pin farther up in the piston. Right? Like a chevy 5.7 rod moving up to a 6 inch rod is 300 thousandths longer, the pistons you buy for the 6 inch rod the pin is just going to be moved up 300 thousandths . I guess the same goes for strokin, say going from a 3.750 stroke to a 4.000 just move the rod up farther up in the piston. Right? Bare with me,, its been awile.

jyna06gt

im absolutely going forged, mainly because i know right now ill be happy with around 600-650 but just like anything else with a motor.. your going to want more later. The main reason for the stroker aside from the added potental hosepower is the fact that no one around my area has one in the s197 body style and also i've never ridden or drove a stroked 4.6 before.

and yes the piston does have to tavel further due to the change in the placement of the crank pin on the crank shaft. The crank pin moves out further from the center line on a stroker crank which in case moves the rod and the piston lower in the cyclinder. Increased stroke makes the piston travel further up and down. Since the amount of time allowed for this movement is not increased, the piston speed increases with a stroked crank (piston must move a further distance in the same amount of time)

I was going to keep my rev limit lower by not going with a big blower cam or a custom cam. My plan is just to use the hot rod cams i already have. and lower my limiter with my tuner.