I always wondered why exhaust port bolts are different?
 

I don't think I've ever heard why the exhaust bolts on the front ports are bigger than the rest . Anyone know the answer to this ?

Re: I always wondered why exhaust port bolts are different?
 

My guess is that they had to support the extra weight of the crossover pipe etc.. Just a guess.

Re: I always wondered why exhaust port bolts are different?
 

Never thought about that, but it seems like there isn't that much more weight.

Re: I always wondered why exhaust port bolts are different?
 

The outlets on manifolds up to and including 1936 come directly off of the front of each manifold, hence the use of 7/16 fasteners there.

Re: I always wondered why exhaust port bolts are different?
 

Makes sense, but why not make them all the same? Seems like it would be easier to manufacture if they were all the same.

Re: I always wondered why exhaust port bolts are different?
 

To add to this a 53 truck 8rt engine they are the same size.
When I was putting headers on mine I was expecting bigger in front they had a y pipe that year.

Re: I always wondered why exhaust port bolts are different?
 

That is not my experience on truck engines. Could those holes have been helicoiled? (Note: I have not seen any '53's, only 48-52)

Re: I always wondered why exhaust port bolts are different?
 

Could the reason be that the larger bolt heads make it difficult
to position them for easy installation?

Re: I always wondered why exhaust port bolts are different?
 

Any 8BA/ 8RT/ EAB series engine I've had, they had the big bolts in front and the others were smaller. Could be that the early engines started with it and rather than change the machinery over, they just kept going with it to save time and money. Probably at the time it made sense, but we'll never know the reason why.

Re: I always wondered why exhaust port bolts are different?
 

Maybe Ford had a fixture mounted to the front for a machining process or manufacturing process and needed the extra support.

Re: I always wondered why exhaust port bolts are different?
 

It may have been an intentional act to allow later engines to be retrofitted into earlier cars as a service replacement. The stock later exhaust manifolds have 7/16 studs to hang both the crossover pipe and the front pipe on. On the earlier motors these are direct onto the front outlet, hence the use of the bigger studs/bolts.

It's more like Henry found he needed 7/16" here, and saved a few bucks by dropping to (or retaining) 3/8" on the others.

Can't prove any of the above, but it's a chat forum ain't it? That's what I'm chatting.

Mart.

Re: I always wondered why exhaust port bolts are different?
 

That's got to be it!