273 head options

[vitamindart]

ok i am working on the little 273 doing a basic re-ring and may mill the block a wee bit. and a cam
it is only a 2bbl non comando
now i have the 66 heads that were on this motor and some later 318 heads as well.
what one should i use and why? i was leaning tward the 273 heads to keep compression up... but know the 318 heads will probably flow better.
then there is the whole aftermarket option.
since when you add up the cost of the hardned seats,valves & possible port work. i could probably buy new ones.

 

[vitamindart]

almost forgot the intended use is cruising mostly but i would like it to have some pep in her step

 

[berlins]

too bad your not more out my way, have 67 273 motor sitting in carport - updated to a 360. Don't forget the intake on a 65/66 273 is different than 67 and newer 273s and 318s. Mine uses the newer intake -

 

[coryw]

too bad your not more out my way, have 67 273 motor sitting in carport - updated to a 360. Don't forget the intake on a 65/66 273 is different than 67 and newer 273s and 318s. Mine uses the newer intake -

I think it's the 64/5 273 that is different from 66 and newer.

 

[pishta]

66 was bolt change year, the 273-318 head flows the same, (same casting numbers after 66) The early heads were closed chambered. Get some 302's and a Weiand excelerator 318 port size intake...done deal.

 

[toolmanmike]

I think it's the 64/5 273 that is different from 66 and newer.

66 was bolt change year, the 273-318 head flows the same, (same casting numbers after 66) The early heads were closed chambered. Get some 302's and a Weiand excelerator 318 port size intake...done deal.

Ding Ding Ding! You win the "Bonus Round" tmm

 

[65Vart]

Later 302 casting 318 heads (mid to late 80s) bolt right on. No valve shrouding from what I am told. The heart shaped combustion chambers and the "swirl port" design are supposed to work good. My buddy on here mike270dart just got a set for his 65. I'm thinking about the swap as well but I have a cool 64/65 only eddy intake I would like to use with the odd intake angle bolt thing plus I just found out my 273 is an original commando 10.5:1 motor so now I don't want to F with it too much.

 

[toolmanmike]

Later 302 casting 318 heads (mid to late 80s) bolt right on. No valve shrouding from what I am told. The heart shaped combustion chambers and the "swirl port" design are supposed to work good. My buddy on here mike270dart just got a set for his 65. I'm thinking about the swap as well but I have a cool 64/65 only eddy intake I would like to use with the odd intake angle bolt thing plus I just found out my 273 is an original commando 10.5:1 motor so now I don't want to F with it too much.

If switching heads doesn't mess with your resto plans the 302's are a good choice. Hardened valve seats and a bit better port flow is a bonus. The combustion chambers are quite similar in design and cc so a loss of compression isn't an issue. If you bolt them on a 64 or 65 block you can use a 66 and up intake. If you go for a aftermarket aluminum intake, make sure it is for the smaller port 273/318 heads. The 340/360 intakes will bolt up but the ports are quite a mis-match. tmm

 

[65Vart]

If switching heads doesn't mess with your resto plans the 302's are a good choice. Hardened valve seats and a bit better port flow is a bonus. The combustion chambers are quite similar in design and cc so a loss of compression isn't an issue. If you bolt them on a 64 or 65 block you can use a 66 and up intake. If you go for a aftermarket aluminum intake, make sure it is for the smaller port 273/318 heads. The 340/360 intakes will bolt up but the ports are quite a mis-match. tmm

Yes ,forgot about the hardened seats, another bonus. BTW , Listen to the toolman. He is a 273 god, check the posts on his rebuild, Hope you don't mind the publicity Mike.:cheers:

 

[toolmanmike]

I'm not worthy! I'm still learning but thanks for the kudos. tmm

 

[vitamindart]

pishta, i have an eldelbrock sp2 intake i got from you a little wile ago figured i would use it. i have to look at the 318 heads i have might be the 302. if i remember correctly they were off a mid 80's squad car.
still have all the 273 adjustable rocker stuff figure a nice little cam will give it some pep
as well

 

[604]

I basically did the same thing you are but with a 1972 318. I went with 1966 273 heads. Home port and gasket match job. Had the shop open them up for 1.88 and 1.60 valves, mill them, and install Edelbrock springs. Thin Mr Gasket head gaskets. Comp cams 223 cam. Nice old NOS LD4B intake (I notched the center divider and gasket matched it). 273 rockers. Windage tray. Deep pan. Let me tell you it runs great! I am very happy with the 273 heads!