Edelbrock 60929 Heads on 400 engine?

[Als73charger]

  I am thinking of buying a set of these for my 73 SE 400 motor. My question is, how much of an increase in HP and compression will I achieve from this?  As it stands now, a stock 400 is rated for only 250Hp and I want to build this engine up as funds become available Al

[firefighter3931]

A 73 400 is a very low compression "smog" motor. Not a good candidate for aluminum heads with it having ~ 8:1 static compression. 



Ron

[Als73charger]

  But would'nt these heads increase the static compression quite a bit? What else would have to be done, short of a stroker kit being installed? Al

[694spdRT]

My #346 iron heads measured out at 90cc's so the 84cc Eddy's will probably not gain that much for you. I have a set of 906's that are shaved down to about 78cc's on my Charger. I used those 906's and steel shim gaskets and with the low compression TRW replacement pistons similar to yours and a decked block I am still only at around 9.5 to 1.

Just a thought. If you don't want to spend a lot of coin right now on the 400 maybe some steel shim gaskets and a set of closed chamber 915's or even 516's would get you by until you can build it up from the bottom.

[Als73charger]

   So who sells re-built closed chambered heads? I can get a set of core 906 heads locally, but to get them machined with new valves,etc might cost as much as new set of Edelbrock ones. Anyone have suggestions where to look for a re-built set of "closed chambered" heads? Preferably a reputable dealer that will ship to Canada. Al

[Ghoste]

Just how much are you expecting a head change to raise your compression?

[694spdRT]

   So who sells re-built closed chambered heads? I can get a set of core 906 heads locally, but to get them machined with new valves,etc might cost as much as new set of Edelbrock ones. Anyone have suggestions where to look for a re-built set of "closed chambered" heads? Preferably a reputable dealer that will ship to Canada. Al

http://www.aeroheadracing.com/id6.html

[Als73charger]

  What am I expecting for compression? I do not know. That is why I was asking what I can expect. I had e-mailed Aerohead a week or so ago, but have not heard anything back. Al

[694spdRT]

Depending on what head gasket you now have you should gain around a point of compression with steel gaskets and closed chamber heads. That should bring you up to around 9 to 1.

Here is a compression calculator you can play with.

http://www.rbracing-rsr.com/compstaticcalc.html

[Als73charger]

 Awesome! Thank you very much.
Al

[Als73charger]

 Update! I picked up a old set of 516's. Look pretty good. I am going to remove the springs and check the guides and clean them up with a wire wheel on the angle grinder. I will clean up the valves as well to see how they look. Hopefully, they won't need major work. Al

[Challenger340]

Sounds like a good find ?

If you do opt for a rebuild on the 516's, or they require any exhaust side work $$, they respond very well to upgrading of the Exhaust Valves to the 1.74", instead of the "restrictive" 1.60" that 516 Heads came Factory with.

ALL the '68 and later "Open Chamber" Head Castings had the 1.74 Exhaust Valves from Factory, 906, 346, 452, etc, etc., so it's a nice enhancement on the 516's.

You don't need to install Hardened Seats for Unleaded Fuel, just enlarge to accept the 1.74" Valves
Then,
Add about 300 mls of 2 Stroke Oil with each Tank of Fuel to prevent Valve Seat recession.
NO,
it will NOT "Blow Blue" like a 2 Stroke, it's just enough to keep the seats Lubricated, and FAR Cheaper than Installing Hardened Seats.

Good luck on the project
Bob

[694spdRT]

You don't need to install Hardened Seats for Unleaded Fuel, just enlarge to accept the 1.74" Valves
Then,
Add about 300 mls of 2 Stroke Oil with each Tank of Fuel to prevent Valve Seat recession.
NO,
it will NOT "Blow Blue" like a 2 Stroke, it's just enough to keep the seats Lubricated, and FAR Cheaper than Installing Hardened Seats.

Good luck on the project
Bob

That is nice and inexpensive fix for that problem. Thanks for the info. 

[694spdRT]

Update! I picked up a old set of 516's. Look pretty good. I am going to remove the springs and check the guides and clean them up with a wire wheel on the angle grinder. I will clean up the valves as well to see how they look. Hopefully, they won't need major work. Al

Hope they work out well. I have a set of 516's on an old 361 that I have been saving for years just in case I need them.