spark plug's

[johan]

hey am back again with a new question
i have my engine ready olds 403 and it's build with these parts.
kb pistons flat top 4.375 bore
COMP Cams Xtreme Energy cam and lifter kit 218 int./224 exh.
COMP Cams Magnum steel roller tip rocker arms
hooker supercompetition headers
ported and polisht 4a heads
edelbrock intake
and the halo gridle from j&s machine
cloyes double roller timing chain.
holly 650cfm carb but i want to have a rochester from cliff
what do you all think my horsepower and torq will be.

and now the stupid question what spark plug should i juse

thank johan

[Dick Boneske]

You haven't given a clue about compression ratio. Neither HP or spark plug choice can be determined without knowing that. If it's 9.5:1, this setup could be good for up to about 425 HP with a Quadrajet. The 650 is kind of small for this engine. If compression is 9.5, I'd start with stock plugs for a 403--or one heat range colder.

[engineer]

carb is fine, smaller is always better to start. stock plug heat range first, then read the plugs and adjust accordingly.