Jeep 4.0 in 69 Barracuda

John,

I know it's too late in this build to change anything; you are already well-past the point of no return and I understand that.

Be that as it may, I was just curious as to why you chose the AMC engine to power this Barracuda when it entails so much adaptation and fabrication, not that there is ANYTHING at all, wrong with the motor chosen.... there's not. As sixes go, it is definitely one of the very best.

My own, personal. choice for this project would have been different from yours,though. My first choice would have been a turbocharged slant six.

There are several reasons for my choosing this engine, not the least of which would have been, it is a "bolt-in" with NO adaptation of anything, since it is a factory option for this particular car. That factor, alone, would have saved a lot of money.

Second, you have had considerable experience with the mechanical vagaries of the slant six, having already built two (?) of them... There should have been virtually no "surprises."

Third, the performance capabilities of a turbo slant six are astounding, to say the least, and I am aware that you are not building a race car, but it would seem that a 400 horsepower slant six in this car would give it all the acceleration you'd ever want/need, and is not very hard to attain.

A turbo slant six is a docile street engine, and even a 400 horsepower version has a smooth idle, good road-manners, and runs the best, both at the drags strip and on the street, with a 2.76:1 final drive ratio (so, no overdrive is necessary for the hiway.) And, turbos eem to like automtics, so, a 904 would fill the bill, nicely.

The 225 slant six is an unusually robust engine, having been designed as an aluminum engine with thick mainbearing webs, thick block sidewalls (no thin-wall castings, here...) and a very hardy, thick, top-of-the block deck (maybe 5/8" thick,) with a matching cylinder head gasket sealing surface in the 80+-pound head that is also unusully robust. The forged-steel crank (in the early engines, has 4 main bearings that are the same size as the mains in the 426 Hemi, so, it's not indestrucable, but is about as close as youre're likely tp find in an nline six. I have a friend who has run as much as 37 pounds of boost in his 225, as an experiment, with no apparent damage. The cast iron engines share all the design parameters with their aluminum bretheren...

I realize that you already know all this.... I am just trying to point out (to people reading this thread, who might not know,) the reasons for the decision I would make, given the opportunity you have with this car. And, I was just curious as to whether you had ever even considered a turbocharged slant six for your project.

Tht engine is not very well-known... it's a too-well-kept secret, I think...

The cylinder head that is the only one available for the slant six, is so restricted (in ways that can't be fixed,) that it can't be made to flow enough air to make much over 300 horsepower, and at that perforamce-level, the cam and carburetion you have to use to get a naturally-aspirated engine to produce that 300+ horsepower, make the naturaly-aspirated version, not much of a "street engine"... too radical.

But, turbos don't seem to work well with lots of cam-timing; too much overlap.... so, the high horsepower (400 and up) blown slants only have cams with short-duration.... so, they idle like a stock motor. Lots of low-end torque.

I applaud your project; I think it will be a HUGE improvement over the stock car it replaces!!!!

I'll be watching your very interesting progress reports. Keep doing the great job you have done so far!