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High compression motor build questions
Hey guys, n00b here and I'm building a 351W, stroking it to a 427 and was wondering what the highest compression ration you can have and still run on 93 octane. I'm trying to get all the horsepower I can out of the motor, but don't want to set the compression too high and mess with the timing so much that i defeats the purpose of it being a high comp. motor. Any input would be appreciated, about the fuel and what parts have worked best for hp gains.
I want something that's still streetable but also a good weekend racer. So far these are the mods I've been planning on doing; this stroker kit from Coast High Performance http://www.coasthigh.com/Ford-427W-F...7-ps-f427w.htm, with these AFR aluminum heads, a custom ground cam from comp cam, wasn't too sure about the intake manifold but was thinking maybe an Edelbrock Performer RPM, or a dual quad, with maybe an 800 cfm Edelbrock carb. If I'm missing anything let me know, or if i left out some info please ask, I'm half asleep while writing this. Foti |
Aim for 10-10.5 and you'll be pretty safe.
Where are you from? |
http://www.clubcobra.com/forums/fe-talk/107902-highest-c-r-93-a.html
Same guy, same question asked here... |
I knew something sounded familiar.
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See here from post 18 on: http://www.clubcobra.com/forums/show...=107902&page=2 So how about helping out a newb-Brent this is you kind of stuff... |
427Bullitt......Only one comment, and that is for your carb choice. Just my opinion, not being critical of you!
I've had several engines w/Edel carbs, and they're OK (for me) if the cams are mild, for stock/medium performance engines. I don't know how much cam you are planning on, but I've never had any satisfaction w/Edel carbs if my cam had much duration, or if I was looking for high performance. I always wound up going back to a Holley/clone. Good luck! |
Be glad to...
Hey 427, give me a call when you get some time to chat. 502.759.1431 |
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Hey Brent isn't that a little to simple of answer? (10.0 to 10.5) Correct me if i am wrong, but what he really needs to know is how much DCR he can get away with on 93 octane. SCR is really ambiguous without more info on the engine build. So what is the safe limit on 93? 8.5 can he do 9.0 (Aluminum heads)?
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No....DCR is a good tool to use IMO when you really want to fine tune a build, but you're pretty much safe with 10 to 10.5 with most street cams and aluminum heads. I use Pat Kelleys calculator and I wouldn't go over 8.5 on 93 and aluminum heads.
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Just ran my figures and have a static of 11-1 and dynamic of 8.59
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For a regular street engine, I usually aim for 10-10.5 and don't have any problems with that and the camshafts that I run. Block prep/piston prep/good machining also eliminates a lot of issues with the higher compression ratios. Eliminating all sharp edges on the pistons, running a tight quench, and running efficient chambers helps a ton. I always try to run about .040" quench on the engines that I build. That means that the block gets machined so that the pistons are sitting at zero deck. |
sorry i haven't called yet, been super busy with some legal issues and keep forgetting.
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