So if a 307 is a 283 bore with a 327 stroke, and a 302 is a 327 bore with a 283 stroke, what's a 305?
Ok, ok, Its a 350 crank in a 3.736 bore block. Considering that the 3.875 283 bore is already shrouding a 1.94 valve, why in the hell anyone in thier right mind would want to build one is beyond me. Now i know someone is going to say "they're cheap, and easy to find." Well, so are fat chicks with ass tattoos, but that doesnt mean I want one...
Whooopy! George!!! Junk 307s are fucking junk !!! I ran all this through Performance Trends Engine Analyzer, honestly, I'm wondering if my computer has thrown a rod or something, the predicted performance of this combo is a little startling. I have actually dynoed engines that I designed in the software before, in my experience, its about 3% happy, but this thing still performs even better than I expected. I got a hp peak of 356HP at 5900 rpm. This is a pretty amazing number for a 206@ 050 intake lobe. The 112 LSA will help upper rpm cylinder filling, as well as contributing to really good idle vacuum numbers the software is predicting 19", which doesnt seem too far out of line, with a sharp tune, the 383 in my brothers truck idled at 21". Predicted Peak torque is 349@4400 rpm, and according to the computer, it first ticks over 300 ft lbs @ 2100 rpm. Dynamic compression is 8.12, I'd be comfortable with this on 91, and you might even be able to skate by on less, especially if you hook up some kind of cold air system. Realistically, its not going to make these numbers, but even if you add a 3% correction factor, this thing looks pretty good. It should make around 340 hp, and around 330 ft lbs peak torque, pretty good for an engine combo that is relatively low buck, and should knock down around 25 mpg at a 2000ish cruise rpm. I've been telling you to come down here and ill let you drive mine. It's just the throw away 305 heads though.
Or vice versa. When all this conjecture/theory comes down its likely choice of a SBC with the basic bolt ons, to cruise long distances.
Now that you mention it, no, but the information has been flowing fast and furious so far and I have not yet taken a step back to digest it all. PM sent....
Is the tiny bore a problem for a low rpm, economy engine? I always thought that a undersquare motor was desirable for this situation.
The 327 came out in Oct of '61, I'd be willing to bet there was a hot rodder somewhere dumping one of those cranks in his 283 (and building a 307) by November 1st, 1961...
Short bus, lmao. Saturday at dinner I told a couple unsupervised bothersome children the windows were flavored. Strawberry on the inside and orange on the outside.
Why not build a Chrysler LA engine ISO a SBC? a 340 built to '70 AAR spec would be cool & might keep the cars resale value better
I want it as it was originally modified, and that was with a SBC. A '67 283, to be exact. Plus SBC parts are dirt cheap compared to anything else. Not interested in resale, either. I tend to obtain exactly what I want and keep it forever.
Yea, my m/t catalog has I believe up to 4" stroker cranks for 283's too not to mention I have an article somewhere from 1962 of an over 430 cube, ( I don't remember the number)bored, sleeved, braced and stroked sbc too. Truthfully there isn't a reason to screw with a 307 right now since the added cost of pistons will get you a late 327/early350 block that'd fit the timeframe a lot of us have built to. Hell in this era of $150 core 327/283's I don't see why to not go traditional, especially since the 010 350 blocks are getting hard to come by in a lot of places
Pretty much everyone is just totally ignoring the emphasis he has placed on part-throttle fuel economy. To me, when someone starts talking about an 1800 cruise rpm, I assume that part-throttle fuel economy is a TOP priority. The path to getting a combination of power and excellent part throttle fuel economy is all about cylinder pressure, because high cylinder pressure = more power per lb of fuel burned ,and higher part-throttle manifold vacuum. But you in the US especially are saddled with shit gas. So this build has to be all about 1) first and foremost, the quality of the burn, so he can run relatively high cylinder pressure on shit gas 2) good low/mid lift flow numbers to fill the cylinder to make good power without a lot of rpm, 3) keeping the fuel in suspension so he doesnt have to use a lot of excess fuel compensating for fuel falling out of suspension and 4) not using fuel to generate power wasted overcoming excess friction(high bearing speeds, excess ring tension, high skirt loadings due to high rod angularity). There is a path to building an LA with good burn quality, but as much as I like them, (I have built a few 340s and 360s over the years for weekend warrior street cars) and as good a platform for making relatively big power numbers, 340s and 360s do not have a great chamber shape, and are actually fairly prone to detonation. In addition to that, the heads have piss-poor swirl characteristics (good for high lift flow, not so good for the burn) and the 340 actually has a 4.04 bore, with all kinds of places for end gasses to hide. The 360 has LARGE journals (means increased bearing speed, relative to the 340/318 and the 307 chevy, see #4) that aint gonna help the cause either. The path that I would choose to building an LA that is going to meet his needs would be a 318 with late model small chamber magnum heads, for the same reason that the 307 with vortecs meets these parameters. The combination of a smallish bore with an active chamber means that you can run relatively more cylinder pressure before you cross the line into part throttle detonation, as compared to a 340/360 Mopar, or 350 chevy. The 350 chevy, again has a larger bore, which means even with the same chamber, it will not tolerate as much cylinder pressure on the same octane as the 307 or 318 magnum based combos would, and it combines that with relativey high rod angularity compared to any of the engines discussed above (see 5) The 273 has the same problem as the 305 based combo, but worse namely that the bore is too small to properly utilize the mid-lift flow characteristics of the available heads(in the case of the 273, the small chamber magnums).
See post 78... oh and if you cant afford these, you cant afford a motor... http://www.ebay.com/itm/Chevy-307-S...stons-8-7-1-rings-/331111406194#ht_821wt_1124
Considering your car weights around 3800 lbs, that truck 350 of yours keeps looking better (to me at least). To get that look you want, find a pair of vintage pre-smog heads & a mid 60's OEM cast iron intake. Get a pair of Corvette 7-fin valve covers & vintage looking air cleaner. Lots of threads here on how to do an early PCV setup on a late motor. I copied a '66 327 vette arangement on my 355. A mid 60's generator, small cap delco, & a pair of 2-1/2" rams horns
All well and good, but the 327 would be my choice. 1.94 "Fuelie" heads. Shorter stroke and while they may be hard to find, '68 327 cranks have large journals so you could use a 350 4-Bolt main block. Who cares about the 1 or 2 piece rear seal on the newer stuff. They used the 2 piece seal FOREVER. Had a 365 H.P. 327 out of a Corvette. Dual quads, in a '64 Impala SS. That car buzzed, and it was a boat. Small block durability is why G.M. is having money trouble.
It's all air mass pumped per unit of time. To increase that one can increase the volume (cubic inches or cc's), the flow rate (rpm), or the air pressure (boost) - or any combination of the three. (Or we can get technical and say it's oxygen mass pumped per unit of time, in which case the oxygen concentration in the air-fuel mixture becomes a factor, as in the case of nitrous oxide injection, for instance, or alcohol fuels.) It sounds like the OP is looking for an engine in a light-aircraft state of tune, i.e. around 0.5bhp/cu.in (or 30bhp/litre) at 2500rpm or less. I'd be looking for around 200bhp from a 350-based stroker, say a 377. Apart from the rod-angle issues that is about what falcongeorge is describing. Edit: how about a "hidden turbo" approach, still built for a low rpm peak?
FG has articulated my use case better than I did myself. There has been a lot of good advice given in terms of how to make more power, bt that is not what I am after. My vehicle will be plenty fast enough with the equivalent of a stock 283 with duals and a Rochester 4GC. That's what I ran back in the day and it was fine - and the motor combos being discussed will give me even more than that. I am OK. I don't race around any more - I did enough of that as a kid, never got into trouble somehow so am OK leaving it at that. And if I feel the need for speed I have other vehicles that are lighter, handle better and have more HP: I would rather go fast in them than a 49 Plymouth with stock brakes, steering and suspension. A big plus is that it is looking like I will be able to achieve something neat with about the least expensive components available. So let's continue the discussion as we seem to be closing in on a couple of super setup options. It is amazing that we have folks scattered across the world contributing. This Internet thing might be here to stay after all.
I don't think you can do that. Unless you have a very late 283. Maybe 67? Correct me if I'm wrong but the counterweights won't clear the block. The late 283's are notched at the bottom of the cyls. Plus if you try to grind for clearance you won't have enough meat in the early 283's.I have been wrong before and I am old. LOL. Lippy
I have been following this thread with great interest. Thanks for the great technical information falcongeorge, 31Vicky with a hemi and speed.factorynz. I wonder how close the numbers would be to falcongeorge's calcs for a 307 setup with HO 305 heads.
Real damn close- When I was playing with mine I went for the highest average across the rpm range, so I left a little off the peak on the table. In all reality it will spend very little time at the WOT high rpm.
I've always loved my SBC small, and my BBC big. But it really comes down to what look you're going for, and the budget. It's tough to keep a nostalgic look on any SBC engine if you run modern heads. Even if you started with a 283 or 327 short block, the newer accessory hole heads will make everyone think it's a 350. I just went through this whole process again, and considering budget I went with the 350 SBC without a second thought. The 327 in my car spun a rod bearing badly, and was beyond what I wanted to have the crank turned. I picked up a complete 350 four bolt main truck motor that had never been rebuilt for $100. The crank alone for the 327 would have cost me more than all the boring, and machine work on the 350, and I'd still need a bunch of other parts. I'll be throwing my old 1.94 camel hump heads back on that were updated to 2.02 with stainless valves and hardened seats, and should be running around 10:1 CR, and 375 hp when I'm done with the build. Nobody but me will know when they look at the engine that it's not the same old engine, and my wallet will be the better for it.
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