So, it’s been awhile since I’ve posted. My project went on the back burner for a bit. Block is at the machine shop currently. My plans for the car is a summer driver. No track. This is my first build and I am looking at an Edelbrock performer top end kit complete with heads, intake, cam etc. Going to use stock crank and rods and I’m not sure what pistons to use. I’m somewhat practical in my performance desires.
So the question becomes, has anyone used the edelbroxk 2092 kit? Any recommendations on pistons?
grab all the spec’s from the Edelbrock kit and the spec’s from your 351w. Enter them in this calculator (http://www.diamondracing.net/tools/) and you can change the numbers of the different pistons your looking at and see what compression ratio it gives you. For pump gas you want to stay above 10.5 ratio. For what you’re doing mild street around 11.5-12.0 would be a good number to shoot for. Edelbrock would most likely recommend a piston to use with their kit.
Opps… don’t think I was awake yet when I answered this. For pump gas you want to be under 10.5 compression ratio not above
Wow, I don’t think I’ve ever heard anyone say this before, care to elaborate ?
If you compress a volume of gas x amount, it is heated up. Compress it more, it gets hotter. You don’t want to exceed the temp that allows self ignition (detonation, preignition). Its the temperature of the charge during combustion that determines auto ignition (spark knock) A general rule you can avoid this by staying under 10.5 ratio. You can go higher as other factors come into play as well depending on your build and how close you check all the tolerance. Like making sure all cylinders cc the same.
I was hoping you meant below and then had gone off-track somehow. Wasn’t sure how you were going to justify those bigger numbers even with aluminum heads
For a 351 and aluminum heads like that I think you can probably get away with pushing 10.5:1 on premium pump gas, but if the block is decked much or the heads shaved (they shouldn’t be if they’re brand new) you could run into some detonation issues.
As was said before, Edelbrock should have a good recommendation.
With aluminum heads, a performance cam (to bleed off some of the static compression,) and a carb and distributor tuned to match, 10.5:1 is streetable with pump premium. I’m utilizing that combo on my '69 351W, and it runs very well. I personally wouldn’t go any higher for a street car though.
