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Discussion Starter #1
Hey guys. Some of you already know I have been working on a project 67 Futura wagon and I got to thinking about pump gas and my 427. Fuel where I live is 92 octane at best. I could order some from the local oil company but that's expensive. I never trusted most fuel additives and I don't know enough about water injection to add it to my machine.
I have heard that you can run pump gas in an 11-1 engine but there has to be a few things in the mix to do so. Like aluminum heads, thicker head gaskets and lots of overlap in the cam specs but I don't know the whole scoop. I don't plan to use the car for a daily driver but it would be nice to take it out on the street every once in a while.
Here's some specs for you guy so you can offer some suggestions;
Cam = 106 overlap, 288 intake and 292 exh. 3.29 lift @.50 with 1.7-1 rockers.
Crank = 4.0 stroke scat crank internally balanced with fluid dampener.
Rods = Carrillo "H" beam 6.2 inch,
Pistons = Arias 22 cc domed forged aluminum
Heads = Victor Jr. 205 int. 165 exh flow = 240 cfm. 72 cc chambers
Intake = Victor Jr. port matched and cleaned.
Ignition = HEI electronic.
Carb = 750 Edelbrock. Haven't done any tuning yet so basically stock.
Tranny = 67 C-4 2700-3000 stall converter
Differential = Factory True Trac limited slip with 3.00-1 gears. I have a set of 3.88-1 I might install later.
Exhaust = full length 1 3/4 primary tube headers. No money for the pipes yet but I will be using 3 in. pipes all the way out the back to just behind the rear tires and probably some nice free flowing mufflers.
Well, that's about it. I don't need a pile of broken engine parts so I hope you all can help.

Premium Member
3,801 Posts
Are you sure you have a 22cc domed piston? That would be 14+:1 compression

If its a 22cc dish it would be closer to 9:1

If its a dish, deck it to zero deck, it'll drive it a little higher and give you a tight quench, then use a .041 head gasket and it'll run great

If its a dome, you'll need different pistons

FYI, my 489 inch stroker has been at 10.7:1 since 2006, both carbed and EFI and it'll run on anything. The trick is having cam and ignition timing correct, a good tight quench, and having fuel and engine temps under control.

Never go thicker head gaskets though and not overlap, thicker head gaskets open quench and make it tougher on fuel, more overlap doesn't affect compression, its intake valve closing point you are thinking about.

Once you get more on those pistons, we'll get you there, the other stuff looks good (the 3.00 gears dont match, the 3.88 will be FAR better, but the build itself looks good)

Premium Member
1,479 Posts
I agree on everything My427stang said. Also, you cam spec saying 3.29 lift can't be correct. Check that again. Ditto on the 3.88's being the better choice. A 3.00 gear will kill that motor.

I'm running just over 10.5:1 with my 347 and it runs just fine on 91 octane here in So Cal.

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