Author	[Modern View]
Lanse 03-02-2013 19:30:52 206.55.217.126 Report to Moderator	Hey everyone... So, we've had a *slight* setback with the V8 tractor build, in fact by some miracle its the first somewhat major roadblock we've hit... Anyway, the guy I bought that POS truck from, what we're basing this build on, swore up and down it had a 305... I bought a nice 305 rebuild kit, then with the help of a few friends, we tore the motor down... Cleaned out a TON of sludge, got everything all nice and shiny... And then tonight, we attempted to start putting it back together. And the #@$^#$ rings wouldnt fit over the pistons... I knew something wasnt right... And measured the bore of the engine... It was a few thousands under 4", but once you figure the ridge out, its a 4" bore, the exact same size as a stock 350. I'm kinda happy because I like 350's, and I'd rather have a 350 than a 305 in this thing, but I'm also pretty frustrated because I have all these 305 parts laying around. From what I understand, the only differences between the engines are the bore and stroke, which would be a good thing. Clearly, I need another set of rings, but what else? I understand the crankshafts interchange, and the bearings I bought fit perfectly into the rods, so I think we're good there... What about head gaskets? I know the heads themselves interchange between SBC engines, but wouldnt a different bore require different head gaskets? I don't know... Just thought i'd ask here... Trying to figure out what (else) Im gonna have to buy... Anyone have any ideas? Thanks in advance... PS I'm currently planning on running a carb setup, with a set of craigslist heads and manifold... Can't figure out how to wire that TBI lol [Reply]   [No Email]
Centex Farmall 03-04-2013 20:09:08 166.137.116.17 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   As others said, the only difference is the bore size, stroke length is the same. All your bearings will fit just fine. The head gaskets are in fact different! The 305 head gasket will stick out into the bore on a 350 and would be bad JuJu! However, you can get away with a 350 head gasket on a 305. Should be no problem finding heads and manifolds on CL. If you are going to ditch the TBI, you will need a different distributor. What you want is a plain jain 4 pin HEI. You only need one 10 gauge, 12V wire to make it work. Very easy to find on any later 70's vehicle. Beware that some early 80's cars and half tons already had a basic computer and the distributor is a little different. When shopping heads and manifolds keep in mind that Chevy changed to bolt angle on the 4 inner most holes for the intake manifold in 1987. Not a big problem but just so you don't end up with mis-matched parts. [Reply]  [No Email]
merlynr 03-07-2013 07:20:50 166.147.104.32 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Centex Farmall, 03-04-2013 20:09:08   Cen tex farmall is right about the head gaskets. My son put a 350 head on a 305 with 305 gasket and it wouldn't hold. Finally figured out he needed a 350 head gasket. [Reply]  [No Email]
timcasbolt 03-04-2013 13:49:53 24.154.92.168 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   Check the head gaskets on the block and see how it fits. A lot of the cheaper rebuild kits are kind of universal anyway. You do need the right rings, though. [Reply]  [No Email]
dr sportster 03-04-2013 12:03:06 173.2.32.148 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   I wasn't going to comment on this .After reading it a few times I will give advice[needed or not hehehe] If the ridge is that noticable you may need new pistons as it is worn past spec. You would mike the cylinder in various spots and record the measurements. If using snap gauges you mike several times and look for repeatabilty. If you don't use plastigauge on the lower end you don't know where you stand [mics are nice but plasitgauge is reality- and inexpensive] . Don't try to hone +.010 - too far to stay accurrate- have block bored{ I have a Sunnen dial bore gauge to confirm this]. If the hone does not clean up the bores [touching and refinishing entire bore] then some oil may pass in those spots.Yes you can reuse the pistons and just rering but you must consider rings seating. To hit entire bore with cross-hatch in that case use a dingleberry hone.[Now your adding cost for tools.] In some cases where a young guy gets an old lady's car and rerings but leaves too much ridge then revs the motor more than it was run at -the rings will break when the rods stretch a bit and allow the rings to travel up and get broken by the ridge where the cylinder narrows. The only other advice is ridge reamers have done alot of damage .For me I like to just favor the top of the cylinder with the hone until the ridge is gone. One to not buy a ridge reamer and two to not cut too much.What ever you do don't leave any of the bore glazed . Sand paper and hand finishing is better than glazed walls. I understand you are doing an econo rebuild but the bore is kind of critical as is the lower end clearance. Check the rods for any nicks visually[without cost worry they would be magnafluxed]. Most engines failure is connecting rod failure as this is by far the most stressed part The part about knowing what you have before ordering you will not forget so I won't elaborate on that. Put that Chevy engine ID site in your favorties.Nothing is more pleasing than starting a rebuild you have done yourself[okay almost ]. [Reply]  [No Email]
David G 03-03-2013 17:57:59 205.215.206.18 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   Make sure and take care of the ridge. [Reply]  [No Email]
Hal/ Eastern WA 03-03-2013 14:17:48 97.115.191.41 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   Learning experience! Unless you have not opened the packaging, I would not expect the parts store to take them back. But on the other hand, 350 parts are about the least expensive of almost any engine. I always try to get my parts after I know what I have and what I need. STILL, I often have to make several trips to the store for every project. I have seen engines work OK after replacing rings, bearings, gaskets and doing some valve work. I have also seen engines where doing the halfway job not work well at all. If your bores are not too worn and/or tapered and the pistons are not burned, scuffed and don"t have oversize ring grooves, reusing the old pistons might work. But it is quite a bit of work to do a "ring job", and not THAT much more work or expense to bore the block, install the proper sized pistons and rings, remove the crank and have it "miked" and if necessary have it ground undersized and reinstalled with the proper size new bearings. Something else I have experienced with small block Chevys is that they seem to wear out their camshafts worse than some other engines, at least with conventional non-roller lifters. I would ALWAYS carefully examine the camshaft and each lifter, and be very careful to put the lifters back exactly where they came from if I decided to reuse the cam and lifters. Break in lube is a must and good diesel rated oil is probably what you should use in it. If you are just going to mess around with whatever you build with this engine, have you considered trying to find a fairly good, running Chevy V8? They made millions of them, and while I have not paid much attention lately, I always used to see GOOD used V8"s advertised all the time. Lots cheaper than putting one together. Good luck! [Reply]  [No Email]
greenday 03-03-2013 06:05:00 216.145.156.206 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   I believe they have different heads so head gaskets wont be right [Reply]  [No Email]
Bob 03-02-2013 22:31:40 64.255.159.192 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   "From what I understand, the only differences between the engines are the bore and stroke, which would be a good thing." Only BORE is different STROKE is 3.48" for BOTH engines. Head gaskets are different, most if not all the rest of the gaskets, bearings, etc. are the same. Some info for NEXT time... B-4 you order parts.... SBCID [Reply]  [No Email]
Brad Buchanan 03-03-2013 13:43:58 74.71.185.165 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Bob, 03-02-2013 22:31:40   Hey Bob. Wow what a resource. Thanks for the post. I have always owned GM or Chevy to be exact but now with this gummint so involved I really want nothing to do with them. I actually asked a dealer if I could order a vehicle without onstar and he said he could not do that. I still love the old iron though....had a '67 ElCamino with a 283 that would really scream. Brad [Reply]  [No Email]
2x4 03-02-2013 22:04:44 206.35.11.174 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   first, check the block number at the back of the block. It's on top of where the bellhousing bolts to the tranny. Prolly 8 digits, no letters. That will tell you what it originally was, 350, 305, 327 etc. Someone may have bored it oversize. [Reply]  [No Email]
Retired Farmer 03-02-2013 20:48:25 64.12.116.141 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   I would take the parts back and get the right ones. Are you reusing the pistons? [Reply]  [No Email]
bobs old iron 03-02-2013 20:22:30 97.122.248.135 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to Lanse, 03-02-2013 19:30:52   my guess, if the rings show that the motor is a 350 instead of a 305, because the rings are to small, that might be a clue the head gaskets are to small to fit the the block to seal the 350 hole,, check with the parts store and see if the number on package would be the same, or if you can return the gaskets for the right ones, depending on return policys [Reply]  [No Email]
VADAVE 03-04-2013 09:24:44 149.32.192.36 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to bobs old iron, 03-02-2013 20:22:30   Comon guys this is a SBC we're talking about; they run from 265 Cu in to 400 cu in. The 265's were a little bit different but from 283 on the block were pretty much the same. Those SBC heads will fit either 305 or 350. Some of the different cu in engine were made by putting different cranks in different bore blocks. I'm trying to remember if a 283 crank in a 327 block makes a 305 or a 302--305 I think. [Reply]  [No Email]
BDT in Minnesota 03-04-2013 12:17:48 66.87.2.24 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to VADAVE, 03-04-2013 09:24:44   302 [Reply]  [No Email]
welding man 03-04-2013 09:28:08 216.115.205.96 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to VADAVE, 03-04-2013 09:24:44   If you put a set of 305 heads on a 350 and don't change the pistons,it won't live,ask me how I know. [Reply]  [No Email]
VADAVE 03-04-2013 16:50:41 68.100.102.215 Report to Moderator	Re: Mistaken Identity... 305 vs 350 SBC in reply to welding man, 03-04-2013 09:28:08   You must have domed pistons. Which means your compression ratio is high. Or you have a really high lift cam. making it an interference engine. Maybe both. [Reply]  [No Email]