Welcome to CHR:
Can you tell us a bit about how this car will be driven? Drag race only or street with an occasional ¼ mile blast? Saturday night cruise in or daily driver?
I’m not an EFI guy so I cannot comment on what’s good, bad or indifferent there. I do think that the Sniper is a lot of money.
A couple things that may need some clarifications:
The 400 requires steam holes in the heads. The heads you’ve selected will need to be drilled for such. Make sure you use a 400 head gasket.
In my opinion, the cam you’ve selected is a bad choice if you plan on driving the car on the street. I’d also recommend that you use a roller setup. Yes, it’s more expensive but flat tappet cams require exact break in and often fail within the first hour of run time if not seasoned properly. As a side note - if you’re on a budget, the extra money spent for roller tips would be better spent elsewhere.
The Torker II is not a good choice for street use as it’s a real dog under 2500 rpm.
And as you’ve already mentioned, the transmission (not to mention clutch) and rear end are marginal in your current configuration and will fail immediately with 450 horsepower applied – especially with sticky tires.
Would you be interested in pulling the engine out and using your $4k for complete rebuild? With a .030 bore and 18cc dish pistons in a zero deck and a .040 gasket you’d be around 9.8:1 with 64cc heads. You need to deck the block to zero as the 400's all tended to have pistons that sat down between .060 and .075 - crazy - I know, but they were low compression engines. Buy a pair of these heads:
https://sdparts.com/i-23901396-sdpc-...g-upgrade.html
For about $1K they are some of the best heads anywhere. SD really knows their stuff and they have properly reworked this Vortec to allow a higher lift. You’ll still need to drill the heads for steam – another $100 at the machine shop to have it done correctly.
Roller cam – stay in the 225-230 duration (at .050") range with a .0500" - .510" lift like this Howards (kit including retrofit lifters)
https://www.summitracing.com/parts/h...5-10/overview/ Remember to use the proper pushrods.
Use an Edelbrock Performer RPM or a Weiand Speed Warrior with a 750 CFM carburetor.
Regards,
Glenn
Turn out the lights, the party's over THIS PLACE IS DEAD!
Dead!