The body and the chassis on the '69 are done and reassembled. I have been considering a head upgrade. Specs as follows:
402 +.030 {408BBC}
Pistons: TRW 2354F30 19.8CC Dome
Deck Ht : .016
Cam: Hydraulic Roller:228/238@ .050 .578/.578
on 112 LSA, Int @ 108CL
Current Heads Stock 290's cut .006
{Have to CC but most likely about 104CC)
{Edited - Forgot to factor in reduced deck ht for Comp. ratio}
Compression Ratio as is w/ .039 Gasket =
Head Volume 100CC = 10.30/1
104CC = 9.91/1
110CC = 9.37/1
119CC = 8.68/1
The dilemna I am running into is all the better heads are 119CC which drops Comp to 8.68/1 I can have these milled to 110CC but will still only get to 9.37/1
Does anybody have any real tested data for GM heads such as 290's with larger 2.19/1.88 valves and mild port work. Given the options {bigger pistons is not one}, reworking current heads seems to be the best way to go.
Down the road, I want to put together a 468 or 496, so was hoping to be able to use whatever I did now on the bigger motor later on. Would hate to cut down a set of open chamber heads only to create build problems later on. There is one head that seems appealing, the Edelbrock Ovals are offed in an angle cut 100CC version that would work well now. Question is would these work on a 468 or 496 later on?
402 +.030 {408BBC}
Pistons: TRW 2354F30 19.8CC Dome
Deck Ht : .016
Cam: Hydraulic Roller:228/238@ .050 .578/.578
on 112 LSA, Int @ 108CL
Current Heads Stock 290's cut .006
{Have to CC but most likely about 104CC)
{Edited - Forgot to factor in reduced deck ht for Comp. ratio}
Compression Ratio as is w/ .039 Gasket =
Head Volume 100CC = 10.30/1
104CC = 9.91/1
110CC = 9.37/1
119CC = 8.68/1
The dilemna I am running into is all the better heads are 119CC which drops Comp to 8.68/1 I can have these milled to 110CC but will still only get to 9.37/1
Does anybody have any real tested data for GM heads such as 290's with larger 2.19/1.88 valves and mild port work. Given the options {bigger pistons is not one}, reworking current heads seems to be the best way to go.
Down the road, I want to put together a 468 or 496, so was hoping to be able to use whatever I did now on the bigger motor later on. Would hate to cut down a set of open chamber heads only to create build problems later on. There is one head that seems appealing, the Edelbrock Ovals are offed in an angle cut 100CC version that would work well now. Question is would these work on a 468 or 496 later on?
