livefast1

it just seemed as tho you were discouraging him from the stroker route due to the compression ratio, could of just been the way i read it tho. in my opinion if i was going the stroked route i would go with a 5.4, the larger deck height and stock rod length would prevent the common rocking of the skirt in the lower portion of the bore......... plus i believe the mmr 5.4 shortblock is like 2600 bux.

rmr1923

not at all, and i wasn't trying to pick a fight over it so i apologize. with the "textbook long" explanations, i just wanted to make sure he understood that an increase in stroke will raise the compression ratio unless he gets pistons with a larger dish to compensate for it. i've known people that didn't know this and ordered their stroker kits with the same piston dish as stock, and then had to return it or try to sell it after they'd already put the engine together. stroker kits come with lots of piston options and it can be overwhelming for someone who's not familiar with it all, so some people just order the -17 cc dish because that's what their stock pistons were. and +1 on the 5.4 short block... there's no replacement for displacement.

livefast1

i apologize i shuda read through a little more extensively my bad.

Ecstasy

ok since you build motors, if i bore & stroke my car from a 4.6 to a 5.0, i have the 4.6 dohc, 97 cobra. how much hp will i get from boring & stroking, of course id upgrade the cams a bit and port & polish the heads. what kind of gains would i expect? just out of curiousity.

oxfordgt

Very little gains from stoking a 4.6L since it has plenty of stroke as is. You need more bore to make power but not enough material for it.

Fobra

boring to a 5.0 on a 4v can net 30-50 rwhp

Fobra

with heads and cams, etc and esp with FI

amoosenamedhank

This is the quote that should be in everyone's sig. This is what is killing the 4.6. Beyond our crappy heads and intake, this is our next largest limiting factor.

texas_stang02

the stock 4.6 already has a pretty long stroke in relation to its bore size. just for comparison, the stock 4.6 has a larger stroke-to-bore ratio than a chevy 383 stroker, so stroking it even further would be pretty useless. i've read that you can only bore a 4.6 up to .030" overbore safely, any more than that and the cylinder walls will just be too thin, and a .030" overbore will only gain you about 5 ci, so there's no power to be gained there. you can have the block sleeved and get up to 3.7" bore, which would net you about 305 ci (5.0L), but i'm not sure that it's a very cost-effective option.

Eagle2000GT

We are running a pretty smallmotor with only a3.55 bore. One of the reason we have "crappy 2v heads" is becausethere just isn't enough room for bigger 2v valves. That's whyFord went with 3v and 4v heads. The Patriot stageIII head has bigger2v valves but you have to bore the motor .030 over touse them.

I have read posts from people who were very disappointed with the horsepower that they got from a stroker 4.6. The most woeful was a tale of a guy who bought a stroker short block which gets its power down low, put on new high-flow high-rpm heads, and a mid-range cam. He was disappointed because even with other mods he couldn't make 300 rwhp. I spoke to an engine builder about this and he said it was very hard to talk customers out of the stroker since they were about the same price as a regular forged kit.

I'm pretty sure you will be disappointed as well. A Procharger, like all centrifical superchargers, get its power at high rpms. Putting in a stroker kit which limits your rpms is a waste of the Procharger's potential. Your best bet would be to get a forged short block with the standard stroke that can run 7000 rpms. This will really bring out the F1As potential.