A converstion about how much compression is too much for pump gas

[240260280z]

Nah, it was just an experiment. Dished pistons and L28 77 block. No valve-piston clearance problems and 260z cam.... Ghetto as I said.

Compression is ~10.3 with the Felpro gasket.

[240260280z]

BTW you can type your own values in the green boxes here (rather than just pull down on the left) to see what frankensteins you can build:

Z-Engine Calculator

[240260280z]

Looking at initial timing and advance in FSM's and engine manuals

1970 17 @ 650 _6.0 mech 5.5 vac and 5 @ 750 12.0 mech 9.0 vac

1971 17 @ 650 _6.0 mech 5.5 vac and 5 @ 750 12.0 mech 9.0 vac

1972 17 @ 650 _6.0 mech 5.5 vac

1973 _5 @ 750 12.0 mech 7.0 vac

1974 _8 @ 750 13.0 mech 6.0 vac

1975 13 @ 800 10.0 mech 7.5 vac

1976 13 @ 800 10.0 mech 7.5 vac

1977 10 @ 800 _8.5 mech 9.0 vac

1978 10 @ 800 _8.5 mech 9.0 vac

1982 _8 @ 800 _8.5 mech 15.0 vac

Edited August 16, 2013 by Blue

[Zedyone_kenobi]

Those 71 numbers are for the non emissions cars Blue, as you know the 71 US emissions dizzy equipped ran 5 degrees initial advance.

[240260280z]

From the above (assuming manifold vacuum is used):

71 timing at idle is 17 +11 = 28

71 timing at WOT is 17 + 12 = 29

78 timing at idle is 10 + 18 = 28

78 timing at wOT is 10 + 19 = 29

[240260280z]

Those 71 numbers are for the non emissions cars Blue, as you know the 71 US emissions dizzy equipped ran 5 degrees initial advance.

Yup, that is shown beside it.

Now I don;t feel bad with 20 degrees at idle with no vac on L24 with triple webers. It is less than stock. I also get 37 at WOT using the ZX distributor.

[madkaw]

I have scheduled some dyno time on Friday morning to see what my car puts down. I will bring some jets and a timing light with me! Should be fun, but I am dealing with a shop full of Brotatoes who only work on LSX engines and Vipers.

Out of curiosity what are your reservations?

... ?

[madkaw]

Yup, that is shown beside it.

Now I don;t feel bad with 20 degrees at idle with no vac on L24 with triple webers. It is less than stock. I also get 37 at WOT using the ZX distributor.

Sounds like you running the same exact set up as I .

[Zedyone_kenobi]

No go on dyno day fellahs, Had to pull kid duty on friday. Wife got called into work and I was playing with my little one. I will have to reschedule...

Bummer.. but me and my 6 month old had a great day!

[240260280z]

A 1971 is always a 1971 but a 6 month old is only 6 months old once.

[Zedyone_kenobi]

That was darn near poetic buddy,

Well said!

[Patcon]

Amen,

My oldest can look me in the eye. I am 6'5".. and my baby just turned nine. That is probably why my restorations take me so long. There just seem to be other things that out rank them...

Charles