edelbrock aluminum heads

[rocky]

0n a 71 super bee 340 do the edelbrock aluminum heads make much more hp than the stock 340 heads? i was thinking about getting the edelbrock heads but wondered if the performance increase would be worth the cost. thanks rocky

[Nacho-RT74]

If they are closed chambers ( which I'm allmost sure they are ), yes you will increase noticeably the hp, no matter the valve sizes or flow. All in all Compression rate is what makes the best gain or loose on our engines. That's what was modified to reduce power ( not on heads but on pistons height ) on the polution battle back in the days.

[DynoDave]

While the 340 heads were a good factory head in their day, it's been 50 years. We have learned SO MUCH about port shape, velocity, and flow. As well as combustion chamber shape. Add in the weight savings, and yes, I think you would be pleased with the change.

A few comments on the matter from '09...

board.moparts.org/ubbthreads/ubbthreads.php/topics/294888/340-edelbrock-heads-or-340-x-heads.html

Sorta related....

board.moparts.org/ubbthreads/ubbthreads.php/topics/2246831/re-eddy-sb-heads-340-motor.html

[Nacho-RT74]

And the heat disipation factor being aluminium

[rocky]

the advertised compression on my 340 was 10.25 . i've read other articles that said from 68 to 71 the compression was the same at 10.5 to 1. will the new heads change the compression ?

[Nacho-RT74]

I don't think any stock compression is actually close to the advertised one. That uses to be on "blueprinted" assemblies but factory assemblies got lots of imprecissions on block and head cuts.

I never have seen any small block with zero piston deck height to trust on a 10.25 CR spec. Even less being all SBs got as far I know, composite headgaskets, not metallic.

Considering stock heads are open, yes, any closed heads ( iron or aluminium ) will increase the CR, which ever will be.

[rocky]

thanks everybody for the information

[DynoDave]

Nacho is not wrong...there are usually deck height realities that come into play you you measure actual static compression ratio Vs the blueprint or advertised C/R. That said, '71 was the last year for the higher C/R in the 340 (and other engines). My '72 340 is the first year for the lower 8.5:1 advertised C/R.

So let's say you have an actual C/R of 10:1 instead of the advertised C/R. With the closer chamber getting you a little bit of that back, and with aluminum heads to deal with the higher C/R, I think it sounds like a great combo.