Looking at these Trick Flow 240 heads. Planned use is a strong street RB engine at the 600 hp level. Difference between there several offerings is spring diameter, retainer material and retainer degrees. What is the best use for street use, 7 or 10 degree retainers? Also, wtth the angled plug design, what headers work best?

I like the 10* retainer/lock's myself,, I run the Hedman Hustler fenderwell headers myself, but not for street use, so I cannot help you there.

IMO
7 or 10 will be fine street strip
I have the steel retainer mid level spring , dual spring,on TF270s .
I use Dougs D452 headers , great fit .
In a 68 Plymouth B body

Tex

buy the heads with the plan already in place to install the recommended spring for your camshaft. The locks and retainers are good quality, but trying to get by with springs already on them 90 percent of the time won't work out after everything is checked.Birdtracker

The different spring choices are so you can match up with the type of cam that you want to run. Flat tappet, hyd roller or solid roller. Once you know the type of cam then pick the head that matches.

Thanks for the good information.

Hedman 78030's are a reasonably priced quality header that fits most B/E body applications and work well with standard port location BB heads.

I have the Hedman 78030's on my currently iron-headed (straight plug) 451. I don't see any way they will work with an angle-plug head.