Build me a 307

[Jacoby]

I need some help. Ive decided I'm keeping the 307 in my truck and want to build it up. I'm looking to go full aftermarket with the parts. Keeping the short block as is. So heads, cam, intake, carb, ignition and that's it. If I can order directly from Summit or Jegs or whoever that's fine. I'm not looking to scour the junkyards for parts or any of that. Ive searched and read what I can and just about everything I find is motors built using parts from other motors or the articles are 10+ years old and some of the parts they did use aren't in production any more or have different part numbers etc. People say use Vortech heads only but you have to use a special intake. People say the heads have to be 58cc then someone else says 64cc is fine. Valves have to be 1.94 but 2.02 will work. Cam this cam that. Its all becoming to much.

The truck wont be a daily driver but I want it to run good. A little lope from the cam would be nice. What I have gathered is these motors react better to smaller parts. So if a small valve head with small CC is better then fine. If a 600 carb is plenty then great. A cam with not a whole lot of lift or duration then ok.

I'm just looking for help to gather a parts list. I'm not looking for the 307 haters or the put a 350 in it crowd to chime in. I like to be different and I like the idea of building on an already good running platform.

Thanks for the help

[Warrens69GMC]

edelbrock 2102 cam and lifters

Vortec 305 heads
https://www.ebay.com/itm/CHEVROLET-5...9UtZxm&vxp=mtr

vortec intake
https://www.ebay.com/itm/SBC-Chevy-D...JaIdDc&vxp=mtr

Edelbrock 1404

[Hollow65]

https://www.speedwaymotors.com/amp/s...2-10-490-14607

[weq92f]

Just a few days ago... on this board.... ( You've probably already seen this ):

http://67-72chevytrucks.com/vboard/s...d.php?t=762135

-klb

[Jacoby]

Originally Posted by weq92f

Just a few days ago... on this board.... ( You've probably already seen this ):

http://67-72chevytrucks.com/vboard/s...d.php?t=762135

-klb

Yeah that's my thread lol! More of a conversation thread. Now I'm looking for parts

[Bentbolt]

400 crank will help build some power. 354ci it's a old circle track cheating motor.

[Captainfab]

I agree with the Vortec 305 heads, but I like the sound of this cam in a 307.

https://www.youtube.com/watch?v=tWyjDNk8dfo

As for the rest of the top end, a 600 cfm carb and a HEI distributor will work just fine.

[hans2]

I love me some 307 - great mileage engines and great torque for thier size. My 1969 K5 had one (thought it was a 350 when I bought it) and it did a fine job. In fact, with today's fuel prices, for a cruiser truck I'd definitely take a stock 307 over a 350.

I know you don't want to hear it, but if you're going to throw performance parts and money at it, you're going to be disappointed if you want to see significant improvements in performance. They just aren't the platform to build on of you value decent performance returns for your dollar.

If I was you, I'd get it tuned up, running really sweet, and do a nice paint job and dress-up kit on it.

Then drive it and enjoy the mileage and smoothness that to was designed to provide.

Good luck with your project!

[68Gold/white]

You have to be more careful with cam selection on smaller displacement engines Over camming one is easy to do. The .050 duration needs to be close to 200 degrees on the intake and exhaust.
The standard Sealed Power universal stock replacement cam CS-274 is a great choice for a 307. Hylift-Johnson lifters are the best lifter made. You can buy direct from the company.

A rumpity cam in a 283 or 307 will kill low RPM cyl pressure, so you lose drive-able power and MPG. A small can't afford to lose any low end power, because it has so very little to start with. 350 and 400 is a different story...
I'm not into E-carbs, but a 600 cfm unit is the largest you will need. A 500 cfm would be fine also...

A stock iron intake is best suited for a small engine like a 307 also. An Edelbrock intake has larger runners which might help at 6000 RPM's or on a 350 or 400. An Edelbrock intake could be used. Just not ideal...

Stock 307 heads would be fine also, if in good condition...

Buy a stock oil pump, nothing high volume or high pressure. It takes power to turn the pump and over thinking the pump takes loses power

[AcampoDave]

I got curious and read about 307 heads. Being a 283 guy I wondered if the 307 had a 58 c.c (similar to the 283 and pre-vortec 305) Apparently they had 70 or 75 c.c depending on the year. I'm no expert but I wonder if the #416 305 h.o heads (which are desirable for a 283) would provide too much compression on a 307 for regular gas due to the 58cc chambers. I don't know much about the vortec 305 heads tho' Edit: found this http://www.crankshaftcoalition.com/w...evy_305_engine has good info on 305 heads

[b454rat]

Originally Posted by Bentbolt

400 crank will help build some power. 354ci it's a old circle track cheating motor.

A 305 with a 400 crank makes a 335...

[68Gold/white]

Originally Posted by AcampoDave

I got curious and read about 307 heads. Being a 283 guy I wondered if the 307 had a 58 c.c (similar to the 283 and pre-vortec 305) Apparently they had 70 or 75 c.c depending on the year. I'm no expert but I wonder if the #416 305 h.o heads (which are desirable for a 283) would provide too much compression on a 307 for regular gas due to the 58cc chambers. I don't know much about the vortec 305 heads tho' Edit: found this http://www.crankshaftcoalition.com/w...evy_305_engine has good info on 305 heads

My 67 283 (original to my 67 Bel Air) had 552 heads, with 64 cc chambers. I did some port work on them and opened up the chambers some to hopefully lower the comp ratio. The 67 283's were advertised to have 9.25:1 compression ratio.

64 cc heads on a 307 would likely make close to 10:1. Not a good thing, possibly. 58 cc heads would also push a 283 too high.

There's more good in the old timey heads than most folks know. Part of the problem is that they've driven an old wore out vehicle with an equally wore out 283 or 307, giving the engine a worse bad rep. that it deserves.

I had an engine builder friend build my 283 in the early 80's. With 552 heads, forged pistons, hined with a torque plate, balanced. Essentially did everything as correct as possible. Even had it dyno'd. Sounds like I was stupid spending that kind of money on a 283. It was my money, you only live once. I put 175,000 mikles on the engine while it was in my Bel Air. It ran as good the day I pulled it out of the car, as it did when I installed it!!! I still have it!!! The Bel Air was from the rust and was ready for the scrap yard!

I know that the 307's did not have 9.25:1 compresion ratio's, I just don't know what heads were stock on them. I'm sure the stock heads for them will work fine AND keep the comp ratio in a safe range....

[AcampoDave]

Jacoby, can you post the casting # of your heads so we know what you have?

[manimal]

307 block, 400 crank, 5.7 rods, ross pistons, World Products SR torquer 305 heads. Engine would run like a bat out of hell. Use to build this combo for a dirt track car that had 360 cid rule. Came in at 359 cu in.

[b454rat]

Said it before, 400 crank in a 305 makes 335. An offset ground 350 crank with .030” over bore makes 357. There is a roundy-rounder track not far from where I am, and 3-4 other ones near by. Plus couple machine shops n engine builders. But do the math for urself and see, not trying to argue is all....http://www.wallaceracing.com/cid.php

[b454rat]

Sorry thought said 305. 307 has bigger bore, and with .030” over comes out 359. Sorry!!

[manimal]

Originally Posted by b454rat

Sorry thought said 305. 307 has bigger bore, and with .030” over comes out 359. Sorry!!

No worries. I knew you'd catch it.

[b454rat]

Always heard these motors called gutless wonders, other than heads don’t know why they wouldnt perform like any other motor with the same mods done. But also whatever you do to a small motor, do same thing to a bigger motor and get bigger gains.

[AcampoDave]

Too bad the o.p never came back. This one had my interest due to the "dare to be different" factor.

[Captainfab]

The 307 responds to upgrades just like any other small block Chevy. Just because they were a low HP engine from the factory doesn't mean anything. So were the 350's and 400's in the mid to late '70's.

[Tom]

I'd take a 307 over a 305 any day for any application.

[AcampoDave]

Originally Posted by Tom

I'd take a 307 over a 305 any day for any application.

why is a 307 better than a 305? I've heard it said many times but never had it explained to me.

[jjzepplin]

My 307 is stock and has high mileage and runs great. Idles so smooth I am surprised. It has the old 2jet carb. I have a performer intake and a Holley 600 laying around. Should I go for it. It also has a HEI dizzy already. New oil pump and timing chain as well as freeze plugs. It was free so no big wup.

[manimal]

Originally Posted by AcampoDave

why is a 307 better than a 305? I've heard it said many times but never had it explained to me.

the 305 is not a BAD engine, but the heads are very prone to cracking.

[Captainfab]

With the same head, a 307 will breathe a little better than a 305 due to the larger bore. But the 305 has a longer stroke which will produce a little more torque.

Originally Posted by AcampoDave

why is a 307 better than a 305? I've heard it said many times but never had it explained to me.

I wouldn't bother with the intake and carb without upgrading the cam to take advantage of the bigger carb.

Originally Posted by jjzepplin

My 307 is stock and has high mileage and runs great. Idles so smooth I am surprised. It has the old 2jet carb. I have a performer intake and a Holley 600 laying around. Should I go for it. It also has a HEI dizzy already. New oil pump and timing chain as well as freeze plugs. It was free so no big wup.