408 build block and head question

[Challenger]

wanting to build 408 have 2 360 blocks date 76 and 85 both 30 over which would be best to use if any differents -- wanting to use eddy heads with tti headers but magaum and performer have different exhaust port design which will work with headers it will be going in 69 dart with p/s thanks guys

 

[moper]

Whichever block is thicker when sonic tested is the best to use. The exh ports are slightly different shapes, but in the same spots wo headers work with both. LA are usually cheaper for valvetrain and intake choices.

 

[Brian Hafliger]

wanting to build 408 have 2 360 blocks date 76 and 85 both 30 over which would be best to use if any differents -- wanting to use eddy heads with tti headers but magaum and performer have different exhaust port design which will work with headers it will be going in 69 dart with p/s thanks guys

The early block will probably be better in cyl. thickness and main strength.
Which eddy head, LA or Magnum?
Porting or no porting?

 

[Challenger]

i have both performer 340 and magnum and there will be porting -i did notice different ehaust ports on the 2 and tti had one design i am confused

 

[rumblefish360]

Most all headers come with the exhaust port shape of the older heads. I wish the companies would change it as well, but it isn't much of an issue since theres really nothing you can do about it. Just use it and be done with it.

What MoPer said about the blocks, which ever sonic checks to be thicker.

IMO, the Edel. head needs work AKA Porting, to work on mild 400+ cube engines.

Whats a Performer 340? (Head???)

 

[Rengo]

340 performer head = T/A??

 

[70aarcuda]

edelbrock peformer rpm heads...aka eddy heads...

 

[moper]

The early block will probably be better in cyl. thickness and main strength.

I've never seen that in the real world. They SHOULD be stronger, but with core shift and crappy casting processes that is not the case. I find the 80s castings are better and more consistent... Sometimes consistently shifted..lol. But consistent. This last '89 vintage is one of the thickest small blocks I've ever tested.

 

[abodyjoe]

wanting to build 408 have 2 360 blocks date 76 and 85 both 30 over which would be best to use if any differents -- wanting to use eddy heads with tti headers but magaum and performer have different exhaust port design which will work with headers it will be going in 69 dart with p/s thanks guys

i say get rid of both blocks and go get your self a roller block. screw those flat tappet cams and retro fit roller cams. waste of money. get a roller block and go roller. no worries about wiping the cam with the poor oil today and easy to do..

 

[340sFastback]

Joe is right if you can get a roller block that will save you tons of money compared to a retrofit roller set up.

If you have the Edelbrock Performer 340 heads I would not use them because they are open chamber.

The TTI headers will work with both LA and Magnum exhaust port configurations. They are a compromise between the two but in most cases they will seal up.