my 340's heads on my 273????

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Dfnsmn34

Dfnsmn34

Margarita Mike
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Aloha!
you all do it...drive and day dream about your car...well it happened again today....hopefully soon (December) I will rebuild my barracudas 273. I started thinking...how do I rebuild her? Engine wise? Stock, mild, radical? I lean hard towards mild-just above stock. (The car is completely stock and original...for the most part...but the engine is tired)
Then I started thinking...hmm I wonder if I should get Edelbrock Heads for my 340 duster (Currently J heads)...then slap the J's on the 273?

Is this stupid? worth it? do-able without hacking at fenderwells etc?

Or scrap that thought completely and just rebuild the 273's stock heads keeping her all together.

dang too many possibilities...ahhhhhhhh.....FOCUS!:read2:

chime in...:-D

Mahalo Mike
 
had a feeling....ok...i'm officially stupid....Mahalo!

Mods...please delete to keep me from continuing, to confirm, my stupidity for the ages!

My kids could see this.....

HA HA!

Aloha Mike
 
I guess I'm in the same dumb boat LOL........ I thought 340 heads would fit a 273 :???:

Aren't 273, 318, and 340's the same?
 
Physically they are the same but the difference in BORE size limits what heads / Valves will fit. I have had 340 heads on a 318 and they worked fine, The small bore of the 273 just does not allow it.
 
.............Yes u can use them if u notch the bores..............but still not recommended as u lose well over a point in compression, as well there is 2much port volume................kim.........
 
I ran them they will fit you have to notch the block, but the 2.02 intake is going to be srouded bad, I used the j heads and the smaller valves worked fine.
 
here is another ?????

What does "notching the block" mean?

Aloha Mike
 
belmateo said:
Okay, and your compression ratio now is?
Click to expand...

Had to mill the 10.5 TRW's down to flat because it pinged at full advance the last time the Government "helped" us with low octane fuel. Heads are milled to NHRA min, .040 as I remember. Felpro .040 head gaskets. Still need to run premium, 92/93. It is a street driven car. There are many combinations that work. I don't think I would try 2.02 valves on a 273. Not worth the risks and hassle for me. I'll look up chamber size tonight.
 
I'd say the cr would be about 7-75 to 8-1 with a zero deck that big head gasket and a 74 cc chamber.
 
66fs...whats your cranking psi last time you checked ?


I don't see the point of doing it if you want more power get a block with a larger bore like a 318 or 340 block. 318 are cheap and easy enough today and kb makes high compression pistons
 
Rob R said:
I'd say the cr would be about 7-75 to 8-1 with a zero deck that big head gasket and a 74 cc chamber.
Click to expand...

CR is more than 9.0. Chambers on these "J" heads are 64.7 cc. They were cut .040 on the block and .038 on the intake side. 273's have higher compression than the poor 318. We even had to put open 318 heads on my brothers "67" 273 so we could run gas other than Premium.
 
dodge freak said:
66fs...whats your cranking psi last time you checked ?

I don't see the point of doing it if you want more power get a block with a larger bore like a 318 or 340 block. 318 are cheap and easy enough today and kb makes high compression pistons
Click to expand...

I don't remember psi. I have a 340 and a 383 in "A" body Barracudas. As for power, the 273 will spin the tires all the way through 1st, 2nd, half way through 3rd and turn them over good into 4th with 4:10 gears. I''ve had this 273 for a long time and it is perfect for an early Barracuda (small wheel wells). With 2:76 gears it will get 25+ mpg cruising at 70 mph.
 
Hey..I thought this was dead! Now I'm more confused. So I could with my 66 LA 273. But I have to notch the cylinder if they are 2.02. but no notch if they are 1.88. Essentially, the head (Valve area) is to big for the cylinder bore. So it might be better to rebuild the original 273 heads and port-polish them when I rebuild. Still limited to the stock exhaust....so if i did the swap I MUST put headers...dang dougs and tti prices....

66fs- that sounds like a fun ride.

hippo- I haven't forgotten your shirts...once a new batch is made. I'll get them for you!


aloha!
 
66fs said:
I don't remember psi. I have a 340 and a 383 in "A" body Barracudas. As for power, the 273 will spin the tires all the way through 1st, 2nd, half way through 3rd and turn them over good into 4th with 4:10 gears. I''ve had this 273 for a long time and it is perfect for an early Barracuda (small wheel wells). With 2:76 gears it will get 25+ mpg cruising at 70 mph.
Click to expand...

8-3/4 rear?
 
Dfnsmn34 said:
Hey..I thought this was dead! Now I'm more confused. So I could with my 66 LA 273. But I have to notch the cylinder if they are 2.02. but no notch if they are 1.88. Essentially, the head (Valve area) is to big for the cylinder bore. So it might be better to rebuild the original 273 heads and port-polish them when I rebuild. Still limited to the stock exhaust....so if i did the swap I MUST put headers...dang dougs and tti prices....

66fs- that sounds like a fun ride.

hippo- I haven't forgotten your shirts...once a new batch is made. I'll get them for you!

aloha!
Click to expand...

You must be careful with the big Intake valves on a 273. My lift was only .460. Stock exhaust manifolds, 2" custom dual exhaust. 8 3/4 rear. 273 heads will not run like 340 heads. I have not tried 302 castings yet, although I do have a set.
 
Your best option is to find some swirl port 302 casting heads from a mid 80s 318. They go right on and you don't have to worry about valve shrouding . Everyone correct me if I am wrong
 
........Yup the 302s r the hot ticket.............they have the small ports and valves 2 keep the velosity up.............kim..........
 
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