If you have the 4.00 inch bore you can get that kind of compression, but with the small bore it just swallows the compression with the bigger cc heads.
So If I run a early Power Pac head, say '58-'62 era, what piston would I be safe running for around 13:1 total compression? Out of curiosity, how high can you go with compression on these small blocks? I know at even this high it will have to run on some mixed fuel but when do things start to get over the top? Thanks again -Dean
I can send you a pic of them.The combustion chamber is all valve.I think stock they are like 58cc chambers.I had them shaved a little.They are ported and polished on both intake and exhaust sides.I had the heads done at a shop here in Pa.One shop told me you couldn't do it the other guy said no problem.Easy way to up the compression.I run 11:1's but with the heads it's an easy 12:1 maybe a little more.I have the heads off right now.I sheared off a connecting rod.So I'm putting together another bottom end.I can easily get you pics and show you what the undersides look like.
There is a company that makes some small CC chambered heads. Speedway sells them. I'll look for a link. http://www.speedwaymotors.com/p/880...vy-Cast-Iron-Cylinder-Head-Straight-Plug.html 50 CC chambers.
If you are going to race the car in non sanctioned events, I wouldn't get all hung up on period correct engine internals. I would just try to get the look and build something reliable, and powerful with easy to find modern parts. That way, you don't have to worry about breaking hard to find parts, or spending tons of money to replace those hard to fiind parts. Especially since you are not building the same engine as it had back in the day, don't get too worried about it. You are not going to run the fuelie unit, and you don't even know how the original engine was configured, and are already considering other internal engine mods that were not available in the 60's (comp nostalga cam, 1.6 roller rockers) so why not build the engine so you can have fun with it and not worry about destroying parts that will put the car down for monthes while you find replacements. You can probably build a 383 stroker or long rod 400 for what you will have in that 283, and make 200+ more HP while looking identical. Some people just get way too hung up on "period correct".
Thats very true and I usually do this, but this car has alot of history (won in the '68 NHRA Nationals) and we just think it deserves to be as authentic as possible. I do know it ran a high-winding 283ci with a Duntov cam, other than that it's just historical judgement. It's like any purist, it's fun seeing how well you can do with the restrictions of the era. -Dean
If they were going for a class win they would have been using anything they could, legally. So it boils down to; what was legal for their class? I think Super Stock would have been the early power packs and a fuellie or dual quad. Some NHRA research is needed.
Has anyone tried running a bored to 4" 283cid block with 6" small journal rods and stock bore 350cid pistons on a 283cid 3" stroke crank? Do the math: it looks like it could work and not torture your bank account. Camel-back heads w/1.94' IN and 1.6"EX with a good pocket-port and port-to-manifold match and screw-in studs is a decent combo (if you can do most of the work yourself). Otherwise buy aftermarket and reshape the head end profiles to resemble the old Power-packs (lots grinding and detailing). To get the raw cast iron look, fill a salt shaker with sifted sand, spray on first layer of paint, sprinkle sand onto wet paint, let paint tack up, then spray 2nd, 3rd or more coats as desired. BTW the 1957 block did NOT have provision for side motormounts; all '58 and up did. Also the core plugs between #1&3 cylinders and #2&4 cylinders are in different locations on the 5-6-7 engines than on the '58 and up engines. Also the little "rib" above the timing cover is shaped differently for each of the different displacement engines. A person could get quite anal about disguising a stroker 350cid to look like a 283! Don't forget the harmonic balancer. The early 283's did not use one; later ones did. Enough said. I appreciate guys who bring back to life the earlier drag cars. Good luck to you on your project.
Power pack heads can be cut for 2.02 valves but it's like pissing in the wind. The runners are to small to take advantage of a 2.02 valve. They are really narrow in the area around the valve guide, and the bowls end up looking like a funnel. I'm not saying it can't be done, I'm just saying it's not worth the work to do it. Jeff
I built a 350 out of a .125 overbored 283 from a Chevy II. I took a 350 steel crank and turned it to a small journal. In the grinding the rods we gave it a little more stroke. This brought the pistons up to the deck nice. It worked good. We used stock 327 rods. The engine is still going. Jeff
I built a .030 over 327 which has a 4.030 bore and a 265/283 crank with 6 inch rods it came out to a 306.
with tons of posts about "you could do this, or that....." how about the guys that have build 283's or 327's chime in with everything that's been done, and what they think of it, or some dynoish...specs/good estimates of that they are making powerwise. do's and don'ts how fast it got you down the 1320 in what vehical..... i'll be doing the same thing in a few months with building my 283, haven't messed with SBC's in years, but gathering knowledge and would really like some REAL world experience
I built a "spare parts" motor a few years ago that was a 60 over 283 block, 327 crank, small generic cam (it think it was 204/214@50 duration) and 307 pistons with 601 casting 305 heads that ran great and got good gas milage. Probably about 250 hp out of 316ci with about 9:1 compression.
So Rick did you just build a bored 307 in essence? BTW, for al of you thinking of building the short stroke motors, don't be disappointed if the numbers aren't what the big 406's are putting out. Everyone gets desensitized to the e/t's. All of the cars these days run way better than the early stuff to spite whatever your dad or grandpa says about their 283. They are my favorite engines, but they won't make the power that is portrayed by some. Just keep that in mind. You'll be doing it for purists sake, not because you will outrun any 406's.
I have a 331 (327 +.030) with ProTopline/RHS Aluminum heads 2.15 intake 1.625 exhaust. Coated 64cc chambers. Zero decked block, .040 head gasket. Hyperutectic flat tops. Scat rods. Solid lifter Ultradyne cam [email protected] .539 lift. 1.6 Scorpion roller rockers. Edelbrock Performer RPM intake. 750 Holley was used as the dyno carb. 72 primary 76 secondary 87 octane fuel 424 hp @ 6200 406 lb. ft @ 4000
To find a 283 block that will bore 4" sort through the pile and try to find one that has HB cast in thr front lower left hand corner. Then pop out the freeze plugs between cylinders 1&3,2&4. Check the gap in the water jacket area. The thick wall blocks will have a much smaller gap.
if building a 283, is it worth looking for the small journal 327 crank/rods to stuff in? is there much power/torque gains? just a thought passing through my simple mind...
Hey guys, went over to Don's speed shop and came up with a game plan, what do you think...early/mid '60s 283 block with a 4" bore, 283 crank (roughly 301 inches as I recall?), by boring it I can have more piston options by using a 350 piston (12 or 12.5:1 pop-up) and can run a re-worked fuelie head and still get high compression, but with the added better flowing characteristics of the double hump head. The Duntov cam is probably out as much more hp can be gained by other choices as some of you said, it will still be solid though. Then possibly a Offy medium rise dual quad intake with two 600's and Stahl headers.......you think thats straying too much for history's sake? Should I push for an actual 283ci engine? I know I could disguise a 383 stroker or something and make a crap load more power but sometimes I get a kick out of building period correct if the project calls for it. Thanks alot for all the input guys... -Dean -Dean
i'm curious , how do you use a 350 piston in a 283 when the pin height is almost 1/4" different? extra long rod?
How historically accurate do you want to be? If you're keeping it in the I/S area, the only dual quad setup that'll be right is the factory 270 hp setup (and have you seen what this stuff is selling for?). If it's gonna be a MP or gasser, then aftermarket stuff is in play. The gain from the 4" bore isn't worth the risk to the block, IMHO, put in +0.60" replacement pop-ups. Best power gain will be with modern heads - not too hard to disguise as earlier ones - plug the accy holes, skim coat with met-all, build up area on front to look like early PPack or double humps. Modern cam will help power, too, and sound like an old one; if not, use an 097 (315 hp fuelie cam). vic
I am working out details for a 283 right now and choices for forged pistons are very limited. About all I can find are Speed Pros and the .030 over are only 8.26 CR. .040 and .060s are 8.30 and 8.36. If anyone is aware of an alternative w/higher CR, please post the info.
Ohh I guess that answers one question. I hadn't been able to find any yet but those wont do for me. He did mention using a longer rod when doing the 4" 350 piston deal. Good point about the manifold too, it will have to be factory Corvette to fit in the class. -Dean
Well, you can always go custom if you don't mind the price. That's probably what I'll end up doing since I have a good block, forged crank, and Power Pack heads plus a brand new set of Scat small journal rods.
If you run 283 bored to 4" you might as well run a 327 block. You could turn the mains down on a 350 crank. Then you could have a 350. If you really want to be sneeky you could have the machine shop turn a 3 9/16 stroke crank. If you use a set of cheap cast 350 pistons they would likly work out, since they usually come to rest around .040 from the deck anyway. Hell if you go for cubic inches might as well go all the way. Jeff
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