1970XL351W

I am not sure it is feasible to add a turbo in my particular situation. But I have been thinking about it for awhile and the right carburetor was for sale and I made an offer on it and bought it. It's a 650cfm blow thru. But I'm not sure I should even attempt the project. My car is a 1970 Ford with a 351W. It was a 2bbl car. It has stock dished pistons. I did some upgrades on the top end. I installed aluminum heads with 60cc combustion chambers. It has one of those thick Fel-Pro head gaskets. I use a hydraulic roller cam which is sold for OBD and power adders, and it is a 270HR .512int/.512ext with 114 deg separation. It has a Performer RPM dual plane intake and a tuned 570cfm Street Avenger. I keep that on there right now due to the 2.75 rear gears and stock convertor with low stall. It really needs at least a 670cfm. My speed shop said 770cfm though for some reason.

Would a cranking compression figure help determine if I can apply turbocharging? I can use the blow thru carb here or just save it for another engine. It is sort of a dream I've had for a long time to apply a turbo. It would be better though if I did it here rather than needing 2 cars, one N/A and then one turbo.

I assume my 351W is putting out an advertised figure of 375-400hp. I really only want to add maybe 100hp max. All of those Windsor engines are 2 bolt mains if I'm not mistaken. Plus, having a lot more power is not kind to the powertrain. But I'll have a stout manual shift C6 and a 9" rear.

1970XL351W

I've search several times for some answers and turned up a little dry. What I mean is, basically, I just want to fill up at the pump with gas that I can buy here and go. I think it is 92 octance. But not 100 octane. And I've heard about injecting windshield washer fluid but would rather not.

Intercooling is also available and I would do that within reason if necessary. I assume I might. But I don't really know if that works when I have my current compression ratio. I think it must. The Porsche Ceyenne has a 10.5 ratio and I am not that high I do not believe. But that thing has a computer for engine management. Maybe not a valid comparison whatsoever.

1970XL351W

I did a little more research and what I learned about my original 1970 engine was that the original compression ratio was 9.5:1 with the original head. So the original head was a 60cc combustion chamber. Which the Edelbrock heads I installed also have a 60cc chamber, so that is the same. Now when I took it apart it had a thick gasket, which I think is .040" thick, and I reinstalled a similar gasket. So even if the head was off before, it really is only the difference between the original (may be .040"?) and the new gasket. So I am coming in at 9.5:1 it looks. Anyone think 6.5psi boost is going to work right?

The cam is another factor I know. Which I know my current cam is a 270H but could go to a 290 H. But anyone have any thought on that? Don't I gain some preignition security by lower the dynamic compression?

Matt Cramer

That should be OK - you could always run race gas or E85 if you have knock issues.

1970XL351W

Hi Matt,

That's sort of what I mean though. I think I might rather own a naturally aspirated car over one that needs special fuels. I actually have never seen race gas or E85 around here except maybe 20 years ago. I am not saying it's not here, I don't actually know right now. That is what I am trying to determine, is if I add an intercooler, will I be able to make 6psi of boost and run on 91 (92?) octane. I don't really need more boost than that to make a good jump in power. It's not stickly about making more power alone. I want to drive the car. I might want to take it somewhere 100 miles away for some reason. That is why with my transmission 3rd is actually 1:1 but I am going with a 3.89:1 rear ratio. That's an upgrade from a 2.75:1 but it's not an all out dragstrip ratio of 4.56:1 which makes it still "streetable". For me it is an important consideration before using turbocharging as well. I want to push the limits a little, but not all the way.