307 stroker. Has it been built?

[nowicu812]

I have been going over old threads and have read alot about 307s and pumping them up. I have a couple of them and a new set of flat tops I havent done anything with. A couple of dead 305s and a few 350s. I was planning to build a 307 when I kept running into threads about a small stroker. Has anyone ever built one? How did it run?
I know the majority will say build a 350.
Just going to put it in a van for hauling stuff. Would like to save the 4.000bores for somthing else.
Never done a 307, would like to mess with it.
I already have a set of .030 flat tops going to waste.
The threads I read were at least a year old, somone must be done with one by now. Thanks

[Brad]

Yep, I keep watching for an update as well- it's in my marked threads folder.

[Sweet72]

334ci is what it comes up to with the 350 crank, I think. The 307 is a good little small block and should be a awesome little stroker, plenty of torque for what you'll use it for. I ran a stock 307 every day for 5 years in the GMC and loved it, but since I'm redoing everything in the truck I decided to build a 383 stroker. Good luck and welcome!

[Bowtie67]

the 307 is a good motor, one of the plus things of it are, that the connecting rod to stroke ratio is the best with the exception of the 327 which is the same out of all the stock GM engines. only real drawback as far as performance goes is that becasue of its small bore you are limited to smaller valve sizes, a 2.02 intake valve will work but will be shrouded thus hampering any performance gains of a 2.02 head. If building a 307 a good cylinder head would be the Vortec heads (1.94/1.6 valves & 64cc) added with flat top pistons, these heads are exceptional for lowend tourque & fuel economy which is what you are looking for in a daily driver, as far as stroking out a 307 unless you have the parts readily available basically at no real cost I wouldnt bother. It is just as easy to pickup a 350 and now you have your stroked out 327. Another advantage of shorter stroke motors are they can rev quicker and as well higher with than a stroker motor wothout spending the bigger bucks to make them do so.

[Tx Firefighter]

I think everyone has forgotten the beauty of the 307 here.

Take your 307 crank and bolt it into a 350 block. No mods needed at all. Now, call your favorite mail order speed shop and buy a set of generic 327 pistons. You now have a 327.

The 327 is truly the little engine that could.

I've been looking for a cheap 307 for awhile now to scavenge the crank and to do exactly that.

[LUV2XCLR8]

December 2005 issue of Classic Trucks has a budget built 307 article
in it, they did a mild upgrade and got 315 hp / 330 ft. lbs. out of it

My 2wd Blazer has the OE 307 / 2 bbl in it, gonna run it till it dies

[69TowRig]

Originally Posted by Tx Firefighter

I've been looking for a cheap 307 for awhile now to scavenge the crank and to do exactly that.

I'll let you know when mine comes out of the Blazer...

[wibilly]

i was always under the impression that the 307s used lower qualitl iron in there blocks and heads is this true?

[Tx Firefighter]

Originally Posted by LUV2XCLR8

December 2005 issue of Classic Trucks has a budget built 307 article
in it, they did a mild upgrade and got 315 hp / 330 ft. lbs. out of it

My 2wd Blazer has the OE 307 / 2 bbl in it, gonna run it till it dies

I read that article. In my opinion, it wasn't a budget build at all. They put Edelbrock aluminum heads on it and lots more. They could have easily bought a GM crate engine brand new that made more power than they wound up with in that 307 buildup.

It's a perfect example of magazine guys scoring free stuff from their advertisers in exchange for some free magazine exposure.

[Bowtie67]

The 307 is already a stroker, it is a stroked 283, bore it .030 and now you have a 283 stroker with 312 Cubes.

[nowicu812]

Thanks guys. I was reading a post were it was in the works.
307 block .030 over.
305 crank (better balance for 307 pistons). 3.48
400 rods. 5,565
307 pistons.
I have all thease parts, just wondering if it had been completed and how it ran.

[woodridge]

One of the performance mags did a budget engine buildoff a couple of years ago and one of the entries was a stroked 307. I don't remember the specs but it was impressive, good enough to get him the top running for the award. I'll try to find the issue and post it.

[Sweet72]

nowicu812, you have all the parts to do it so go for it, keep us posted on the progress. I didn't want to get too technical but I couldn't help myself...

If my calculations are correct the 5.565 rods, 3.48 stroke crank and 307 piston compression height of 1.655 you get 8.960", and with stock sbc deck height of 9.025 that leaves the piston .065" in-the-hole.

With the 307's stock specs, 5.7 rod, 3.25 stroke and compression height of 1.655 you get 8.980" or .045" in-the-hole.

That .065" in-the-hole will drop compression considerably from the stock CR of 8.7:1.

[nowicu812]

Sweet 72 may be right. Im using the caculator on the silvolite site. I get -.027 in the hole stock and -29 in the hole stroked. I dont know if its right . Can someone else check it.

[nowicu812]

Silvolite told me the 30 over pistons would give me about 9.2 to one with a standard(.040) gasket at about .020 in the hole with the stock crank. Thier calculator says 9.039 to 1 at 27 in the hole, 9.179 to 1 at .020. I need to find somone good at this before I go farther. If it will work out I'll do it and keep you posted, just dont want to do it blind. If Sweet 72s right i may be done already. Thanks

[Bowtie67]

Originally Posted by nowicu812

Silvolite told me the 30 over pistons would give me about 9.2 to one with a standard(.040) gasket at about .020 in the hole with the stock crank. Thier calculator says 9.039 to 1 at 27 in the hole, 9.179 to 1 at .020. I need to find somone good at this before I go farther. If it will work out I'll do it and keep you posted, just dont want to do it blind. If Sweet 72s right i may be done already. Thanks

Ideally you want to have a quench between .035 - .045 any thing more than this tends to possibly add detenation issues. Because this block has been around awhile and if you have the rods put one of the old pistons on it and install crank to find out what your actual deck height is and as well to make sure you have enough clearences.

[nowicu812]

I was thinking it would be .029 in the hole. I was going to have the block decked a bit to just to make sure its nice and straight(5-7) and use a felpro .015 gaket. ending up in the quench zone you mentioned. I have a cracked 307 block also that I havent town down yet. I was thinking the same thing. I can put one of the old pistons on a 400 rod throw the 305 crank in an see how it ends up. Im going to email silvolite and have them check the numbers again first. Thanks.

[Sweet72]

Yea, definitely do a trial fit on the setup then you know for sure where you stand. I think it will work out just fine if you tell your machine shop exactly what you want for quench and give them the parts to double check everything. Don't assume they know what you want, be specific.

[nowicu812]

I guy Im going to use is an old school drag racer. Has his personal machine shop only builds a few motors a year on the side for friends. Hes forgot more about small blocks than I will ever know. He said he'd do the 307
(A bit reluctantly, got the 327 speech untill mpg was mentioned). I havent told him about the stroker idea yet, he may have already done it. I wanted to do my homework first. More so I dont look like a complete Ass wasting his time than to impress him, Plus he is 95 miles away ( have to go outside a town of 200 to get um done right)

If he doesnt talk me out of it for reasons I should already know it will get done. If he blows a big hole in the unicorn I'm going after then I"ll just do the 307 straight up. Will report back either way.

Thanks for everyones input. Way to help out the new guy.