Project Muscrate:
Getting a “head” of the curve, Part 1
Hi everyone and welcome back! Boy am I excited! I’m not sure if I can even put into words the feeling of freedom from the ultra restrictive rules of Stock Eliminator brings me. Not that I didn’t enjoy racing in Stock all those years, I did, but the engine builder part of me that always gets tired of confused people asking me at the track why I only run in the 11’s (12’s with the HO combo.) after ALL the years I have raced the Mustang has really had enough and wants to be UNLEASHED!
I can understand the confusion to a certain extent because the average bracket racer or spectator doesn’t have a clue as to what is involved in campaigning a competitive Class car. But geez, I have engines in some of the fastest cars in the area. Do these people think I just can’t build something fast for myself? Well, we are going to find out. Let’s see what happens when you stick a “no rules” engine in a good Stock Eliminator chassis.
As I stated last month, this will not be an ultra high dollar engine. I am planning and executing a build up of a 347 stroker with everyday available parts that nearly everyone with a realistic budget can afford. Some of the parts may be of an unfamiliar nature to the average reader, but I know my readers are far from average! At the end of the series I will tally up the bill for such an engine and provide all the part numbers available. So let’s get going!
To me the single most important component of an engine is the cylinder heads. If there is one thing I have learned over the years from running Stock it is that most factory heads for the small block Ford SUCK! In the past I was forced by rules to use the factory E7TE castings on the HO engine and the unmodified X302 heads on the crate engine. The X302 heads were a dramatic improvement over the E7TE HO heads to the tune of about 45 cfm at .500” valve lift! But that’s still not saying much for the X heads. They peak out at around 215 cfm at .500” lift on the intake and 141cfm on the exhaust.
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| The finished intake port (left) and exhaust port. | |
I have figured that to produce the power that I want (secret) I will need a head that flows about 300 cfm at .700” lift on the intake and just over 200 cfm at .700” lift on the exhaust with a nice big fat curve. At this point I should say that you should be aware of getting caught up in the “cfm at peak lift” game that some cylinder head companies try to emphasize. As was the case with the “Stocker” heads, the area under the curve is at least as important. Anyone can make or port a head to show big top end flow numbers, but if the
mid-range sucks so will the power! What I want is a head that has as small of a runner volume as possible that still flows the cfm I want. That way you will have a port that not only puts up good numbers on the flow bench but has a good velocity to boot. The velocity will make the engine really responsive, giving it that “toggle switch” effect when revved up.
So, bearing all of that in mind, I decided that a head with an intake runner volume of between 200 and 215 cc’s would be the best bet. Originally I decided to just buy some 215cc heads and bolt them on. But then I thought about it and figured that this would be a good opportunity for a tech article demonstrating how to do basic head porting. There is a large selection of different brands and types of cylinder heads available for the small block Ford. Many of them are good, some are great, some suck, and many of them are outside of my budget. Over the last couple of years I have built a few customer engines utilizing the Pro Topline brand of head. I have always been impressed with the flow curve of those heads, but when it got to be a problem even getting any of them I became dismayed.
