Im planning to build the motor for my 49 over winter. Right now I have a 1970 307 out of a C/10 in my garage that supposidly has 30k on it but has a wiped cam. I have the possibility to get a free 1958 283, but it needs a total rebuild. Im looking to run fuelie heads, tripower, and block hugger headers on whatever motor I run. Its going to be backed by a 4spd. Would it really be worth the extra cost to get the 283 over redoing my 307?

I'm probably wrong about this, but isn't a 307 a stroked 283? If it is, your probably better off using the 307.

Either engine will move the car. Both have a small bore, but would accept large valve heads without physical interference at the sort of lift used in mild applications. The larger valves may be shrouded and not flow like they should, though.

I'm suspicious of 307s ever since I heard that some were cast with no added nickel or tin, making them prone to excessive bore wear from the soft iron used.

It won't cost a bit more--and maybe less--to go with a 350, and the added cubes would be fun.

Tri-power? Rochester or Holley? (My choice was Holley--twice the carb the Rochester is. Offenhauser manifold, and even managed to stuff an HEI back there.)

Im not picky about which tripower I use. Its mainly going to be whatever I can find since it appears to be tricky. Right now Im bidding on a rochester setup.

If considering the 283 (needing a rebuild), why not alos consider a 350 shortblock? The 283 core might be free, but how much would a 350 shortblock core cost?

And if rebuilding anyway, how much will pistons be for a 283, versus a 350? Most pieces will be the same, but because of the age (and relative obscurity now), 283 pistons "might" be more expensive, with less choice to taylor CR to the heads you plan to use...

If considering a full rebuild, how much more to get a basic crate 350 (aren't these like $1200-$1500 Brand New?)? You want to add different heads, etc anyway...

just some thoughts...

I guess you could always throw some rings/bearings/gaskets at the 307 and see what happens...

307s came out at the wrong time and got a bit of a bum rap. The manufacturers were starting to lean out the carburetors and retarding the timing to meet emmissions standards. As a result the 307 didn't seem to work much better than a 283. I had a 307 '69 Chevelle with over 100K miles and it ran fine. The 307 has the same stroke as a 327 so it should make a little torque if set up right. It may not be a racer but then it wasn't meant to be.

I am going to get around to building another junk 292/301 motor onna these days, but it is going to be an 8,000+ rpm screamer since my first junk301 would go to above 7,000+ easy with no more than an old -097 Duntrov solid cam.

305HO, -601 heads, .015" thick shim headgaskets, a 600 Holley on a 300-36 Holley high-rise, a 280/246 solid cam and 1.6 ratio rockers for a net lift of right at .500", small tube headers and shooting for as close to, or even slightly above, 10 to 1 CR. that I can get!

Oh, almost forgot, a cheap set of Elgin's, .600" lift, Z-28 type springs, retainers and locks kit.

It's gonna be onna those, "when are you gonna shift her" motors just like my first junk301 was, but higher rpm'med this time!! He, He!!

pdq67

It's that old bore vs. stroke combo that hexes the 307. With the small bore of the 283 & the long stoke of the 307 you have to breath more deeply with a 307. The added stroke give more low end torque, and that move a heavier car more easily, but the longer stroke give longer piston travel (more distance to travel per stroke). When combined with the small more (limiting valve size) you have an engine that doesn't like to rev like the short stroke 283, but doesn't breath as well as a nice 327 with big valves (not all of them were big valve versions). Given the costs to rebuild any small block, you are better with more cubes from a 327 or 350. Still a 307 can be made to generate some good power, but the costs to rebuild it are not co-measureate.

A 1970 307 will still have decent nickel content, and with a set of 305 H.O. heads (1.94" / 1.50") you will have decent breathing. The 307 was not offered from the factory in a high performance version (1.72" / 1.50" only), yet the bore / stroke combo is better than a 305, which was offered in some hipo versions. A 307 is better than a 305 in purest terms as a starting point.

Do a simple stock rebuild on the 307, except for adding some forged pistons on top and a little more cam... then slap on a 100 shot and go have some fun. :D I drove the pee-pee out of my 307 before I pulled it out, you can't kill those things! It only ran a 16.2 in the 1/4 mile, but it was tough as nails. I ended up selling it for $100 to a guy that was going to drop it in an old pickup to haul brush and garbage with.

OR, you could build a 350 as many have suggested, only re-use as much of the 307 parts as possible such as valve covers and brackets. Do the manifolds and stuff like you mentioned. Noone will know the difference, they look identical! Take away the headers and fuel pressure regulator, and only the most discerning eye would notice that mine isn't a stock 307: http://www.69boo307.com/images/regulator.JPG

Well I'm probably going to go with the 307 as long as its clean when I rip it apart. What would be some good parts to throw at it? I was thinking some 1.94 fuelie heads, unless the "good" 305 heads are easy to get. My friend showed me a nice solid-lifter 283 cam, i guess its close to the fuel injected 283 stock cam. I want to keep the bottom end stock, but the upper end is open territory.

If you go with flat top pistons, the 305 head won't be of any advantage that you can notice. 1.94 cammel humps will work just fine, and may be more in keeping in the style you want in the '49.

TRW made flat top forged pistons for the 307 and I saw a set on e-bay about a month ago.