5.7l mercruiser gen 1 alpha 1 to vortec head swap problem please help...

[Scott Danforth]

I am pretty sure you were running lean. your comment on plugs looking clean would collaborate.

I know when I put vortec heads on the '88, and changed the cam, I was running 75 primary jets and 92 secondary on the Holley 715 (up from 2 primary and 85 secondary) I may have been running a tad rich, however the plugs were caramel colored.

my concern is the head gasket blow out. only once have I lost a head gasket on an SBC, however I was way too happy with nitrous.

 

[Paintman1960]

I am pretty sure you were running lean. your comment on plugs looking clean would collaborate.

I know when I put vortec heads on the '88, and changed the cam, I was running 75 primary jets and 92 secondary on the Holley 715 (up from 2 primary and 85 secondary) I may have been running a tad rich, however the plugs were caramel colored.

my concern is the head gasket blow out. only once have I lost a head gasket on an SBC, however I was way too happy with nitrous.

Love it "

 

[Mr.Ferrari]

I am pretty sure you were running lean. your comment on plugs looking clean would collaborate.

I know when I put vortec heads on the '88, and changed the cam, I was running 75 primary jets and 92 secondary on the Holley 715 (up from 2 primary and 85 secondary) I may have been running a tad rich, however the plugs were caramel colored.

my concern is the head gasket blow out. only once have I lost a head gasket on an SBC, however I was way too happy with nitrous.

Thank you for the input. I figured the head gasket blow out was due to high cylinder temperature. Bank 2,4,6,8 blew and bank 1,3,5,7 looked as if it was about to go between cylinder 3 and 5 When I pulled the heads off.

 

[Lou C]

The QJet I have on mine is the original carb this engine came with and when I replaced the heads 4 years ago I stuck with the pre Vortec heads so I didn’t have to change the jetting in the carb which is pretty close to ideal judging by how the plugs look (light brown). I agree with signing up at Cliff Ruggles’ site join the forum there and explain what you have. You’ll probably get the best QJet advice you can find. He also sells jets, metering rods etc that you might need to get it right.