How to cut MGB inner fender for RV8 headers

[skootch13]

Hi guys.  I will be cutting openings into my inner fenders for RV8 style headers.  I have two questions.  One, Is there a pattern somewhere I can use?

And two.  What tool do I use to cut the fenders?  Air powered jig saw?  What blade?  One of these?  https://www.harborfreight.com/5-Amp-14-Gauge-Metal-Shears-64609.html?event_id=184606&hftm_sc=&hftm_source=google&utm_source=google&utm_medium=cpc&utm_campaign=21901270715&campaignid=21901270715&utm_content=169550067559&adsetid=169550067559&product=64609&gad_source=1&gad_campaignid=21901270715&gclid=CjwKCAjw857RBhAgEiwAI-1yKE29hA3AWLFjhpS31ZCkRu8JMae6tp1xVEGCsp4rMufHV9ZqYqyxLRoCSFAQAvD_BwE

[BlownMGB-V8]

I would lean towards using a holesaw. You could cut out some paper circles and stick them where you think the opening needs to go, overlapping them where needed. Each one only needs support for the pilot hole. Then other methods can be used to smooth and enlarge the opening.

Jim

[skootch13]

I like that Idea, Jim.  Slow.  Methodical.  Can be controlled.  Then grind away rough edges.

[MGBV8]

Back in the day, there was a pattern to get one started.  The exact hole location will depend on engine placement & header design, of course.

[BlownMGB-V8]

A die grinder and large carbide burr speeds things along nicely.

Jim