Realistic difference 340HP vs TTI early body headers 273

Yes. The original version of the Dougs headers were used.

I say this with all the love I can. Understand I don't know how to sugar coat stuff.

Get your head outta your *** and stop worrying about every last little bit man. It's not a race car. You're not competing with it. Can you AFFORD 1K for headers? In your situation, they will not add an amount appreciable enough to warrant that type of expenditure. Period.

Look, you will be MUCH happier with the permanence of manifolds. They last forever. A good set of HP manifolds will be ALL you ever need. Don't get caught up in all the BS forum hype. It's just not true. Keep it simple man. You will be glad you did.

No offense meant.
LOL.... RRR put his arms all around you.... But just so you know, there are 10 second cars out there with manifolds...... Not the easiest way to get into the 10's, but it's been done. So, YOUR 273 with a mild cam will not be shot dead because of no headers....