Are these 73 Heads?

[Calvin C.]

I have a 73 454 convertible, it has a 1969 passenger 427 block, about 300 horse. The engine runs smooth can drive it the trans is shot. The carb and intake are corectly dated and number for the car. I just checked the head numbers and they are

(358049) dated (1 21 72), this could be a line then 2 a line then 72, (GM8t) and the word (Pass)
Are these the correct heads and how will they work with a 1969 300 horse 427. Any idea of port or compression ratios
thanks
cal

[Clem Z.]

Re: Are these 73 Heads?

are you sure the # is not 353049 which are 73/84 454,122 cc chambers,255/119 cc ports

[Clem Z.]

your CR will be low as your 427 engine

should have 96.4 cc heads. i have seen 2 different specs for the chamber volume of the 353049 heads,122 and 113 cc.

[Calvin C.]

Re: Are these 73 Heads?

Clem
I thought I copied it down corect but I am sure it is most likely is 353049
thanks
cal

[Calvin C.]

Re: your CR will be low as your 427 engine

Clem
So, If the 427 was a low horse power to begin with, say 290 horse or so, then the 454 heads will be lower?
Cal

[Clem Z.]

the lowest HP 427 in 1969 was 335 HP and the

lower CR because of the 454 heads with bigger chambers will kill some HP and torque