My 307 Build Up

[LilD]

Nice to see somebody building something other than a 350. Nice work.

[oldgold70c10]

Sweet build! Nice to see a 307 getting some love.

[philthethrillohio]

all thistalk of 305 heads on a 307 , i got some 307 heads really cheap theyhad rollers in them rebuilt and real nice mill on them. i never measured for cc but im assumiong it was under 60. never could find stock cc on the heads but new most 307 truck heads were 64cc. anyway made my truck run great! i originslly had the ho centerbolt heads and these ran better

[Ryan5O]

can we get a report on your mpg since the build

[Bert W]

I geared up for the same type of build on my 307. I bought all of the goodies needed and found out that my 68 307 block was just to far gone. casting number said it was a car, and not a truck, 307, so I don't know if it was original or not, I thought it was. I was really looking forward to this build up. Glad to hear yours is working out. I look forward to future updates

[Firebirdjones]

Looks like he hasn't posted since last year. Glad to see someone else building a 307, as most don't bother. Not a bad engine with a 3.25 stroke (same as a 327) it just has a small 3.875 bore.

I did something similar with my 71 Ventura Sprint. It was an original 60,000 mile car with a factory 307 chevy and 3 speed manual. After hybernating for 30 years I pulled it out of retirement.

It started and ran fine but decided to pull the 307 for a regasket. Then for giggles I got a little carried away. I left the short block alone, as assembled in 71 by GM.
Pulled the original 307 heads, milled .020 for a bump in compression (factory 8.5:1) and pocket ported the heads, valve job, new seals, new springs, and reinstalled with .015 head gaskets to keep compression up.
Final compression was 9.2:1.


I used a Comp Cam XE 262 grind (218/224 @ .050) and .462/.470 lift with 110 lsa. It was ground on a 106 LSA but I installed it 2 degrees advanced (104LSA) to try and pull a little more bottom end grunt out of the 307.

I topped it off with an Edelbrock Performer intake and a 600 holley double pumper. I ran 1 5/8 headers on the car too.
I backed it up with an M20 muncie (I had that in the car already 25 years ago) and I still ran stock 3.08 gears. The car weighed just over 3200 lbs. without a driver.
After some wideband tuning and rejetting of the carb for a 12.7 AFR WOT seemed to run best. And it liked 40 degrees of total timing, and ran perfect on 91 octane.

For performance results, I did make several dragstrip passes for giggles while at a muscle car show. The car surprised me with a best of 14.17 at 99 mph through the exhaust on stock tires with a 2200 DA reading.
It also cruised easily at 70 mph and knocked down 18 mpg.

I was happy, for a little 307 it ran great, power shifted that thing at 6,000 rpms for 2 years without a problem, and outran bigger engine cars with it. I have since pulled it for a long retirement, and a stout 406 went in it's place

[Hubscrub]

Originally Posted by LilD

Nice to see somebody building something other than a 350. Nice work.

X100

[WORP67]

I know this is a old thread but has anyone done this recently? I have the 307 in mine. I picked up a set of the 416 heads with a fresh rebuild for free and wanting to help out my motor and freshen it up. I am having trouble deciding on cam and carb/mani setup. My truck also has has long tube headers already and swapping to hei dizzy.
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[Firebirdjones]

Read my post just above. I posted that just this past November.

They aren't bad engines, more of a high winder if you want to make any power. Doesn't make too much sense to build one from scratch when cubic inches are king and it doesn't cost anymore to do so. But for tinkering around purposes it can be fun

Not sure about your head choice, but original 307 heads have a smaller combustion chamber to keep compression up (only 8.5 factory) so putting anything on there with a larger chamber is going to kill power.
You might want to cc those heads to be sure, something to think about...

[WORP67]

The 416 heads are 305 H.O. heads with 58cc chambers. Smaller chamber than stock so should up my comp a little.
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