351W build

Make your Cougar run faster, handle better, and jump higher... okay maybe not jump higher. If you feel the need for speed, this is the place.
Post Reply
ccall29
Registered Member
Posts: 26
Joined: 25 Jan 2016, 18:06

351W build

#1

Post by ccall29 » 04 Jan 2018, 18:57

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?

Thanks in advance
The Old Gray Mare, '68 project

User avatar
BossElim69
Supporting Member
Supporting Member
Posts: 2089
Joined: 07 Mar 2011, 13:18
Location: Michigan

Re: 351W build

#2

Post by BossElim69 » 05 Jan 2018, 06:51

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.
Brian Carpenter, President CATS classic Cougar club
67 Cougar road course racer
67 Cougar project car
67 Cougar GT
68 XR7-G trailer queen restoration.
68 Restomod
69 Boss 302 Eliminator
69 XR7 390 survivor
69 XR7 428CJ 4spd
70 Boss 302 Mustang
1993 Harley Davidson
2004 F250 diesel
2004 Jeep Overland 4.7L H.O.
78 Ford F 150 Ranger
08 Cobalt SS

User avatar
wish
Registered Member
Posts: 128
Joined: 05 May 2017, 13:12

Re: 351W build

#3

Post by wish » 05 Jan 2018, 07:36

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.
Wow, I don't think I've ever heard anyone say this before, care to elaborate ?
Just my $.02
wish
69 Cougar, That 70s Truck, 84 Cherokee Chief 2dr, 88 Grand Wagoneer, 95 Grand Cherokee,96 Mustang

User avatar
BossElim69
Supporting Member
Supporting Member
Posts: 2089
Joined: 07 Mar 2011, 13:18
Location: Michigan

Re: 351W build

#4

Post by BossElim69 » 05 Jan 2018, 09:30

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.
Brian Carpenter, President CATS classic Cougar club
67 Cougar road course racer
67 Cougar project car
67 Cougar GT
68 XR7-G trailer queen restoration.
68 Restomod
69 Boss 302 Eliminator
69 XR7 390 survivor
69 XR7 428CJ 4spd
70 Boss 302 Mustang
1993 Harley Davidson
2004 F250 diesel
2004 Jeep Overland 4.7L H.O.
78 Ford F 150 Ranger
08 Cobalt SS

User avatar
wish
Registered Member
Posts: 128
Joined: 05 May 2017, 13:12

Re: 351W build

#5

Post by wish » 05 Jan 2018, 10:37

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.
Just my $.02
wish
69 Cougar, That 70s Truck, 84 Cherokee Chief 2dr, 88 Grand Wagoneer, 95 Grand Cherokee,96 Mustang

ccall29
Registered Member
Posts: 26
Joined: 25 Jan 2016, 18:06

Re: 351W build

#6

Post by ccall29 » 05 Jan 2018, 12:16

Ok guys. Thanks for the responses. I saw that compression # and I was confused. I don't know much, but that didn't seem right to me.
The Old Gray Mare, '68 project

User avatar
cj750
Registered Member
Posts: 517
Joined: 26 Nov 2011, 19:42
Location: Siloam Springs, Arkansas

Re: 351W build

#7

Post by cj750 » 09 Jan 2018, 14:50

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.
Every post I make comes with a request for corrections. I'm here to learn.

1969 Cougar Eliminator 351 4V, yellow
1970 Cougar Eliminator 428SCJ, black

Post Reply