350 build

[eventhorizon66]

1980c10: You are correct; you should have a shade over 9.5:1.  That's assuming the pistons are 25 thou in the hole.  This is a great street compression, but 89 or higher octane will most likely be required.

bobcooter: With a zero decked block, 76cc heads, 0.040" thick gaskets, and 7cc relief flat tops pistons you've got less than 9:1.

There are a ton of compression calculators out there.

http://www.kb-silvolite.com/calc.php?action=comp

[bobcooter]

Wow, thanks.

[bobcooter]

Here's a little interesting reading on the subject of vortec heads and piston selection.
http://www.customclassictrucks.com/techarticles/0405cct_vortec_cylinder_heads_small_block_chevy/index.html

[1980c10]

the .025 deck clearance is a complete wag.
the block will only be surfaced enough to clean it up and has never been rebuilt before.
Does anyone know what a realistic number or range might be on this^^^?
With a zero deck I would be at 10:1 so your concern is very real and definatley made me do my homework on this.
I am waiting for the block to be re-assembled at the moment to get an actual measurement from the the machine shop.
btw: http://www.baxterengines.com/
On a side note;
My carb should be ready to pick up in the morning considering I dropped it off this morning that's pretty amazing so we'll see- he said he had nothing to do today until UPS arrives with parts so he would work on mine right away.
My intake is supposed to arrive in the morning also.

[eventhorizon66]

No point in guessing what your compression height will be; just wait for the short block to be assembled.  Either way you'll be between 9.5 and 10:1.  And 10:1 should be perfectly acceptable with premium pump gas, especially with vortec heads (I imagine that article was referring to trucks that weigh a bit more than yours and that see regular towing).  I certainly wouldn't worry about it for a weekend cruiser.  If you are worried about excessive cylinder pressure just slide in a bigger cam.  It would be a good idea to know what CR you end up with, though.

[1980c10]

yeah I definatley want to know where the compression ratio ends up at. I got my intake in today and picked up my carb. I dropped off my carb less than 24 hours ago and is done and ready to run. I told him when I dropped it off to also make it look good if he can and it looks better than new. I'll get some pics of it one of these nights. Anyway it is painted cast iron gray with the throttle plate and choke painted silver I don't think I've ever seen a quadrajet look so good.
   This carb has the old style choke and my intake doesn't have the area machined for it. I am thinking I'll try to run it without a choke and use an ac selenoid and a switch to activate it to bump up the idle at start up. I will only drive this truck in the summer. plan B would be to install a choke cable.
^^Thoughts?^^Anyone running without a choke?

[78 Chevyrado]

Find an E-Choke kit, they're worth their weight in gold if you plan to drive it under 50 degrees.  Choke cables are for lawn mowers and 2 ton trucks.  If you have it set up to start without a choke in that cold of weather, it won't be at it's best when running at operating temp.  there's no possible way to make that heppen except for EFI.

[1980c10]

78 Chevyrado
Sounds great except, I don't have a hot air choke, it's a divorced choke. There isn't a kit available for this that I am aware of for a vortech intake that will work with this type of choke.
A choke pretty much gives the engine a richer fuel mixture, I am thinking I can do that by giving it a few pumps before starting it. The switched a/c solenoid could turn up the idle a few hundred rpms until I shut it off after it's warmed up. I am hoping this works. Like I said plan B is to set up a cable but I am hoping to avoid that as I am trying to keep the engine bay as clean as possible. The carb builder says it will start with a few pumps and that I would need to hold the throttle for a little while 'till the smooth idle comes around. He says he wouldn't hook up a manual choke.
I've never run without at least some kind of choke, so I have no idea.
Anyone out there run without a choke before or even just a manual choke?
Thanks again everyone for your help and patience.

[79HIGHSIERRA]

dude im jealous you have a beautiful beautiful truck an one heck of a hot rod congrats and good luck man

[Grim 82]

A few pumps on the pedal won't replace a choke, but I realize this is more of a summer driver. Worst case scenario you will have to hold your foot on the pedal to warm it up a bit. Cold engines like fuel. I daily drive mine with an electric choke Holley in below freezing temps, and it's nice to have the electric choke to keep the high idle up while I shovel the snow from in front of the garage in the morning. If you have a functional choke you can walk away and let it warm up, and it doesn't matter in my opinion what kind of choke it is as long as it works. I like electric chokes but there isn't anything wrong with a cable controlled manual choke. Like Kenny said, you can adapt your carb to electric choke. It's stand alone on the carb and doesn't care what intake you have.

[1980c10]

Grim 82
I haven't been able to find a conversion for a divorced choke such as mine.
I have found plenty for the warm air to electric choke coversion, if anyone knows of a divorced choke kit let me know where you found it. With no choke I would install an a/c solenoid to bump up the idle with a switch. This solenoid normally is turned on when your a/c is running to turn up the idle so the a/c doesn't pull your idle too far down. I would instead install a switch This would be my alternative to having to hold down the gas pedal to warm it up.

[Grim 82]

If you get an electric choke equipped q-jet off of a parts truck you could possibly swap those components over to your carb, but that would probably involve taking it apart again. The only electric conversions that I saw online would also have to be mounted to the intake, so yeah it looks like you might be out of luck there.

[1980c10]

Well I can sell my carb for what I have in it and do it again(builder would sell it for me), I've considered this but I'll try it first without a choke and maybe a choke cable.

[screamin86]

what cam did you end up going with? i ran the 1103 cam in a 305 in a car i had and i run the same cam in the 350 thats in my k10 and i love it!

[1980c10]

This one
http://www.summitracing.com/parts/CRO-00904/
I didn't get it from summit as my machine shop is a wholesaler for them.
Didn't want to offend someone there, it was cheaper than the same cam from summit anyway.