307 CHEVY HELP

[Gbody_Ghost]

I just picked up a 307 Chevy not Olds thinking it was a 350 the guy told me it was a 350 and I looked up the casting Numbers (3970024) comes back to a 69-73 Chevy 307, either way, I want to Put it into my 81 Monte Carlo 229 v6 I know I need to replace everything but my goal on the 307 is 400hp I'm not sure if this is possible on this motor but if it is how can I achieve it while on a budget of 5k, I picked up a th350 that I'm gonna bolt to still don't know what rear end most likely an SS rear end or GN maybe ford 9 IN still not sure But my goal is to get it all going by August 2024

 

[UC645]

If you want a 400hp small block, you know what I'm going say next: Ditch the small bore block.
Could you make 400hp out of a 307? In my opinion: maybe. But I have a feeling it’ll involve a radical setup and a lot of RPM to do so.
Grabbing a 350 from a newer C/K1500 should net you a decent block, but the Vortec cylinder heads are a toss up with cracking issues.

But before I continue, is your budget of $5K just for the engine, or is it everything you mentioned?

 

[DRIVEN]

Sell it and go buy a Vortec 350. Stab a better cam in it, bolt an RPM Airgap with a 3310 on top, and then some decent headers That is your most cost effective path to 400hp and easiest swap Into your car.

 

[bracketchev1221]

Can it be done, yes. If you were attached to the motor I am all in favor of odd combinations. But if you are strictly after a hp goal, the cost of machine work is all the same whether you do a 307 or start with a 350. And just to put it in perspective, a mild street engine that makes 1 hp per cubic inch, you are already giving away 43 hp. So if you are after a hp goal start put with a bigger motor and be ahead of the game. I am a big fan of doing the machine work to make the power. Deck the block, hone it square, get the clearances right, and the motor will perform. You can just bolt stuff together and make some power but do it right and it'll make more.

 

[78Delta88]

Basically you have a 283 with a 327 crank.

The problem with that is a lot of money to get where you want.

If you want to stay old school and be budget friendly, get a 350 CID 010 4-Bolt block and put that crank in it. It's a "large journal" 2.45 crank and no mods are needed. Go hypereutectic flat tops, bushed rods, after market heads even the DNAs are getting better, or AFR, etc..., Air Gap or Vic Junior Manifold, Holley 650 DP Spreadbore or 750 vac secondary. Depends on how you want to drive. Go to rock auto and get a Delco HEI distributor, Summit (Elgin) cam [email protected] ratio lift, and [email protected] duration. M55HV oil pump 5/8 tube.

This will be fun driving and budget friendly 327. Or you can get a 350/400 and do the same.

Or for 5k you are already in the ball park for a 383 stroker.

Or stay as a 307. You might get away with heads but most are for 4 inch bore. So you have to be careful when going past 1.94 intakes on the smaller bores. 307 is only 3.875 inch, so would be very close. 305 Vortec OEM heads would be good or 305 HO 416 or 601 casting which are 1.94/1.5 or 1.84/1.5. If you have machine shop do the heads focus more on exhaust. 1.94 intake with 1.6 inch exhaust is much better than 2.06 intake and 1.5 exhaust.

You can keep the 307 as is.... Upgrade the cam, intake and carb plus a good quality distributor. Have the heads done, but you will have to add hardened seats. Machine shop would know this. Call Engine Tech they probably have a kit for whichever way you want to go and it used to be..., over $500 they give you jobber discount. Or also Rock Auto had complete kits...

However ... 400HP is a big no. HP is Torque x RPM (Simple Terms) so if you could get it past 7000 rpm... Like 11,000 maybe you would get close to 400 HP, but then explode.

 

[78Delta88]

There was a Ford 9 bare housing available recently already setup for GBody, and at a reasonable price. I think another member here has it ... If not sold already.

I'm always in the hunt for 8.5.

 

[SS_Malibu]

If I'm not mistaken, isn't a 307 a 2 bolt main block?
$5,000 is almost all the way there for a 383. And even closer for a 355. Built and ready to go.

 

[Ribbedroof]

Naaaaaawwwwwwws!

Might make 400, once. for a brief moment

307s were always a dud

Listen to these guys, many better choices for the money it will take to build a 307

Owning a 307 is like owning a 267....nothing of value to be had from one.

 

[pagrunt]

I'd say a 307 is better for a cruiser that just needs enough power to get out of its own way. They are perfect for a 220-230 build. I can't see one living long near 400 let alone passing 300.

 

[DRIVEN]

^^^This^^^