Quote:
Originally posted by Brad Pfeifer
Andy, Thanks for this information. I did not know that Summit had a stroker motor. Where did you find out about it, and how do I ask about it (I haven't seen it in their catalog)Brad
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Well Brad, they don't sell a crate stroker as such. They did a series of tech articles on building 3 strokers. I think it was titled "Stroker's Wild" and they started first with a 347 build up and I think it dyno'd at 400hp. They then did the 393 build up and then they did a monster engine...a 514 or something. These pages do not seem to be on their site anymore and I had to re-find the shopping list on the TrickFlow site.
OK! I just found them with Google
347 Stroker
http://www.summitracing.com/tech/how...02stroker1.htm
393 Stroker
http://www.summitracing.com/tech/how...ker2/index.htm
520 Stroker
http://www.summitracing.com/tech/how...02stroker3.htm
Summit Stroker Additional Tips
http://www.summitracing.com/tech/how...02stroker5.htm
and here are the same articles but they seem easier to read on the TrickFlow site. TrickFlow promotes them since they were the heads used on these engines
http://www.trickflow.com/articles/st..._st_1_body.htm
http://www.trickflow.com/articles/st..._st_2_body.htm
http://www.trickflow.com/articles/st..._st_3_body.htm
I think a friend and I priced out the Summit 393 parts list and it is somewhere between $6500 and $7k if you buy everything on there which makes it more economical to almost go with the Ford Crate. If you enjoy building things yourself or have some of the parts, the Summit list might work well or help act as a guide for the things needed.
Regarding the reliability of the 393 vs the 427. I personally think they are very close in terms of reliability. many people wil spout of that the 393 is "so much more reliable" when I would say there are probably 10-20 owners of 393s on this board and 10-15 of the 427s and the reliability posts seem even. Here is a cut and paste from a previous post of mine on reliability vs stroke
RELIABILITY
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I equate engine reliabilty with Piston Speed. Since this is directly proportional to RPM, you can have a 200,000 mile 427w stroker if you redline it at 5k (if reliability is what you are after)
Piston Speed Calculator
http://www.prestage.com/carmath/calc_pistonspeed.asp
I believe the coast 427 stroker has a stroke of 4.170". With a 6000 redline, that equates to a 4,170 feet/min piston speed. With a high caliber component crate engine, I think anything in the 4000 - 4500 range is acceptable. If you want huge reliability, 5k redline (3,475 feet/min). If you want a solid engine with tons of torque, 6k redline (4,170 feet/min). If you want to flirt with the edge of the envalope, 7000k (4,865 feet/min)
Here is an example of 3.5L Oldsmobile engine that buzzes to 10,700 in the Indy Racing League and this is 4,650 feet/min. Their 1999 engine was pushing 4,800 feet/min
http://www.indyracingleague.com/pre...ent-122399.html
From SuperFlow.com website on Torque Vs Speed:
http://www.superflow.com/support/su...rquevsspeed.htm
A more telling determinate of power is stroke. The speed at which an engine develops its engine power is usually determined by the stroke. Typically, maximum power is developed when the average piston speed is between 4,000 and 4,500 ft/minute (20 to 23 meters/second).
...from the 4,170 calculation above on a 427 with a 6k redline, it looks like the engine is right in that optimum range.
if you want to find more members with these engines and read how much they like them, check out the links here to other posts on the subject
http://www.clubcobra.com/forums/show...5&pagenumber=2
hope this info is useful
Andy
http://www.cobralads.com