Car Modification

I purchased my first car on a cold day in January at the age of 16. It was a red 1969 Mustang coupe, picked up for $1,800, and I still drive her to this day. The search for my first car lasted over a year, while I worked to save up my money. During that time, there were many makes and models of old cars—I knew I wanted a classic—which I looked at and test-drove. While I was still not certain what car I would end up buying, there was one requirement that I had to adhere to by order of my parents: I could not have a V8. Safety, insurance, the fact my parents actually knew the damage I was capable of were all reasons for this call.

Resolved to this fact, I knew I would have to make due with whatever I could get my hands on. I ended up with the Ford 250ci straight six, and hopes of one day swapping her out for something with a bit more sauce once I had finished her restoration and left home. For the time being, in an effort to hide my shame of rocking a six-banger, I installed a set of split headers from Clifford Performance, complete with a pair of 40 series Flowmaster mufflers. A cutout rear valance with dual tipped pipes added to the effect, and people continue to be fooled and shocked when I tell them it’s a six. I say still, because after a few more modifications I decided to stick with the original engine and continue with the shock factor of putting eights to the test.

The first thing to do is getting acquainted with your online resources. The two I have found to be the most productive for my six-cylinder needs are Clifford Performance—where I bought my headers all those years ago—and Classic Inlines. Both of these companies’ sites have articles, how-to’s, photo galleries, dyno results, and engine parts. I would say familiarizing yourself with the products both companies offer is key prior to making any plans for that rebuild. Of course, knowing what you want from your car modification is key at this point as well; are you still wanting a daily driver with average fuel economy and some nice pep, or are you striving for an 11 second drag machine?

If you are a true gear head, you may end up doing the modification yourself. If not, make sure you have a mechanic who knows a thing or two about this sort of modification. Not only is this an uncommon task—especially in the States—but the average mechanic might not be as well versed in working on old inline sixes. Shop around for your guy, and think about getting him involved from the very beginning, and not when you finally have all your parts and are ready to go. Odds are, your mechanic will be pretty stoked about taking on such a unique project—unless, of course, you find someone who does the mod frequently.

The number one issue with modifying the Ford straight six is the unfortunate problem with the intake manifold. Sadly, the Ford 170-200-250 intake manifold was cast as part of the head, meaning it cannot be swapped out. There are kits that allow you to bore into the manifold to add extra carburetors, but this method has always seemed sloppy to me, and obviously irreversible. The Ford Australian six, however, does have a detachable manifold, and these heads are very popular for inline modification. The only problem is—living in America—these heads are very difficult to come by, and even if you buy the head from Australia, the shipping will kill.

A more viable option is to simply purchase an aftermarket head from Classic Inlines. Not only will you then have the option to swap out manifolds, but they also have an aluminum head to make the purchase all the more worth it. Odds are, even with the Aussie head you would perform a complete rebuild, and with the aftermarket you can just order it with the new add-ons already there for you. Performance rods, rocker arms, and springs are all elements with will help beef up the power-potential of your head.

Classic Inlines has you just about covered in all aspects of your car modifications. Their master rebuild kit will get you where you need to go, and I highly recommend going that route over building up the parts one by one. They have several options that allow you to completely customize your package. At this point, it is really important to have done your research and know exactly what you want, and hopefully know what your mechanic recommends; because there is a good chance he still knows more about it than you do, even if this is his first six modifications. 

In the case of my ’69, I opted with the C.I. Aluminum 250-4v head from Classic Inlines, also adding the Clay Smith S294-122 Camshaft and Lifters, SI 1.86/1.56 Valves, the Yella Terra 1.65 Roller Rocker Kit, and a Romac High Performance Balancer. I decided to go bold, and skipped the carb, going with EFI fuel injection instead—giving me great mileage and performance. I still make about 24 MPG, and dyno’d at 256 HP and 401 lb/ft of torque. At a recent car show, they had a 150 ft drag strip set up for us, and I completely blew the doors off of my brothers ’71 351-4v Mach 1.

The common fate of most six cylinder classics—particularly mustangs—is to gut it and drop in the eight. Hopping up the old six was a blast, and is such a unique addition to the story of your ride. At car shows, my ’69 gets unbelievable amounts of attention because people have never seen a six dressed up in such a way. She performs well on the road, while also getting my better fuel economy than I probably could have expected from a stock 302. At the same time, it gives me a sense of satisfaction knowing the heart that beats under the hood is the same one that was dropped in on day one.

Jack Payton is a car nut in the purest form. He loves to write about everything gear related, and rebuilt his first engine at 15. He works as the online publisher for the online tire retailer tires-easy.com. In his spare time he enjoys cruising, attending car shows, and collecting vinyl.