so i have been debating doing a 351w swap for my 66 mustang and i know it might be a little much for now a days but it would cost me about the same amount of money as to do a 302 swap into my car if i bout a engine kit from PAW engine parts and that way when i decide to go insain i will have a good solid starting point so i have been debating it. my question is the headman swap headers say that they will not work with a toploader tranny. what is the reason for this and could they be made to work because the hooker super comp headers are a little expencive and if i dont have to use them i would rather not also could a toploader 4 speed hold up to the torque of a 351w..i know there are alot of forms on about the swap and i have been looking them over the last few days nad could not find the information i wanted. i know alot of people are against it because of the tight fit and the extra weight but i still think it would be fun but anywas just let me know what you guys think and i would be glad to hear it thanks again :SNSign:
ps. the car is a 66 coupe with a toploader 4 speed and a 289 and i believe a 8 inch rear end but i do not know for sure or how to check so any info on that too woudl be sweet
The truth is that there is no readily available 351w swap header that fits perfectly in the 65/66 engine bay. The engine compartment is very narrow and these engines are an afterthought for the very early Mustangs. Each header manufacturer will have its quirks. Some do not cover the 4 speed because there is not much room to bend the tubes to allow for the factory z-bar.
I have used both Tubular Automotive and Accufab headers and know their limitations. The TA's just plain suck for fit. The Accufab's fit OK, but are not the perfect solution. As I said, I doubt that you will find a perfect solution from any of the handfull of manufacturers of the swap headers. It literally takes me 2 hours to remove OR install the Z-bar in my Accufabs. There just isn't much room for 4 header tubes, the engine block, the steering box, and the Z-bar to all route through the same area. The ground clearance I have with my Accufabs borders on phenomenal, so I that is the main reason I recommend them on the forums. I like the fact that although they are hard to install, once in, I can forget that they are there.
Lets play find my Z-bar:
If the thought of dealing with the swap headers turns you off and you are going to be building for less than 425hp, I suggest taking your 289 and building a 347. Their lighter rotating mass makes for a very fast and fun accelerating car. All the 289 external parts will fit perfectly and you have a much wider assortment of headers available.
As far as the strength of the toploader, don't worry. As long as you don't have one of the very early (and fortunately quite rare) 25 spline output shafts, it will take tons of abuse. The same basic tranny was used behind the Boss 409, the Boss 302, and the 428CJ. The ONLY mechanical differences were the enlarged input and output shafts, which you won't need unless you are putting 500 or more HP to the ground. These puppies are tough. If you should break the toploader, all parts are readily available through some good internet sources.
As far as how to check for a 9", if you can place a deep socket on the lower mounting bolts, it is a 8". If there is no way, then you have an 9". The 8" will live for quite awhile behind a 351w or a 347 until you try to install sticky tires. Then a 9" is your friend. Visit Kevinstang's site for some info on 9" ID. Here is one of his pics that show the mounting bolts I mentioned:
