Exhaust port shape

[AzPete]

Trying to get some info without removing the headers for now. The '66 has '69 351 cast heads. Need to know if these would have square or round/oval exhaust ports.

Looking at maybe some new headers but the fitment issues from Summit and Headman clashes with this info..... Headman 88406 have square ports but headman says I have oval ports....hmmmm. Summit lists the same headers as oval ports which Headman says is wrong.

 

[camachinist]

They're square, roughly. I have some C9 351W castings in the shop if you need pix or measurements. Mine have the smog norbs in them, some of which I removed many years ago.

As a comparison, the 429/460 heads in the shop have 'oval' exhaust ports.

 

[AzPete]

Thanks.....that tells me that the Headman 88406 shorties should fit with no problems.

 

[camachinist]

If they look like this:

No worries.

 

[AzPete]

This is the gasket Headman says goes with the headers...

Interesting that the set pictured from e-bay has two holes missing....

 

[1497]

Pete, I've mentioned this in other posts but will say it again here. I have those headers in my 68 bolted to GT40X heads. The fit and finish are excellent.

 

[AzPete]

I keep reading that......and the fact that it is a '68 ('66 is a bit narrower inside there). Just wanting to verify every angle I can before ordering. I hope to do the swap in one day. Plan is to destroy the long tubes in the removal since they are in bad shape on the lower two tubes and collector rings. Then do the new install.

 

[camachinist]

With the OEM mounts and in a 64.5 chassis, I had to slightly dimple my JBA's for proper clearance. I don't know if that's the case with the Hedman's in the later chassis. Something to be aware of when fitting. They've worked fine for 20 years so the little 'tweak' at the beginning was no big deal.