Is it reasonably cost effective possible? What would the expected outcome be? HP and fuel econmy. Thanks this looks like the right place to ask.
If the journal diameters are the same or could be machined to match the receiving block, you'd be giving up .230" of stroke.CID = bore x bore x stroke x 0.7854 x #of cylsCase in point, 3.736 x 3.736 x 3.25 x 0.7854 x 8 = 285If it bolts straight in, using 305 pistons and 5.7" rods, the loss of stroke leaves the piston and additional .23 in the hole on top of the factory deck height. Using a 6" rod adds .3 to the overall length but then the piston is .07 out of the hole, above the block deck. You'll need custom pistons with either rod length. Then it will have to be balanced or it will kill itself quickly.While it sounds cool, like a 283, the 305 block has some of the smallest bores of the family. The only blocks to have smaller bores are the 262 & 267. It CAN be done but the cost and labor would hardly be worth the effort, IMO.
+1 ScottWhy would you want to do that. Get a 4" bore block, and if you want destroke it to a 283. Then the heads with 2.02/1.60 will fit in the cylinder without any shrouding.Unless your plan was to just go smaller. Let us know what you want to do. Bob
All true about a 305 and 307. what combination can be made that results a worth while enginge? I have a 307,305,327 block,350 heads and voretc heads. 305/307 are not worth the outcome. a 327/307 crank,rods and pistons im not sure what I have but need new to fit bores. and vortec heads. Im trying to make a the best combo without going exotic.I guess the 305 heads on the 350 would be more cost effective.
Is the 327 a large journal block? Even if it's not, with its 4" bore that'd be the one to use with the Vortec heads.Even though the sbcs parts are mostly intechangeable, mixing a crank from one displacement with a block of another displacement, then mixing in pistons to fit will require a master balance man make it work. Removing weight just takes time, adding weight takes time & money. The 307 & 327 have the same stroke while the 305 has the same stroke as a 350. The 305 crank with the 327 block will mathematically yield a 350, making it work balance-wise might be an expensive nightmare.
THANK YOU VERY MUCH SCOTT.This is exactly the information and rational thinking i need.Ok that leaves out the mouse motors. I have a virgin 400 small block and a 402BB.Im lookin at puting one into the 74 el Camino. Vortec heads on the 400 vs 402 which has roller rockers at least (not sure of internals.) Tour the country with gas price in mind. maybe a little toyhauling mixed in. Which would be the better choise?How would you fuel it cost effectively?
400sbc = 4.125 bore & 3.75 stroke396bbc = 4.094 bore & 3.76 stroke402bbc = 4.125 bore & 3.76 strokeDepends on which 400sbc block you have and which 396bbc you have. Later 2-bolt main 400sbc would be the better choice of 400sbc. The 396 blocks got a bigger bore starting in 1972 and kept the same stroke for the 402bbc. Depending on application it was billed as a 396, 400, or 402.You can read about that in the wiki link.http://en.wikipedia.org/wiki/Chevrolet_Big-Block_engineGiven the price & availability of parts in conjunction with the parts you have on hand, if it was me, I'd build the 400sbc IF you have the stronger 2-bolt version. Start by having the block thoroughly inspected for cracks AND cylinder wall thickness before buy anything for it. That goes for any block of unknown condition/origin.On the other hand, if you actually have a later big bore 396, you could get a crank kit and go with the longer 4" stroke for an oddball 427. I say oddball because a factory 427 had the same stroke as a 396 with a larger 4.25 bore.
OH MAN, I reread your last post after I wrote my last post. Sorry I got off on a tangent.If both blocks are in good to great condition to start with and the after assembly CID is within 15cu.in., I'd say go with the small block because it weighs less.
Thanks again!I like the first response. I do have the later of both blocks. The difference is the 400sb will require a rebuild , for that matter so will the 396/402. With the vortec heads in hand and maybe roller rockers added the cost should be about the same as the tear down and rebuild of the 402 with rockers already. Ill have to look in to 402 to see what has been added beside the rockers. cost wise I will have to add new fuel setup for the 400. Which maybe in my best interest for todays fuel options.got any build tips?Ill have to drag the engines in and start a closer look.Thank you again for the advice, saving me lots of soul searching. Now to go search the garage and start the retirement project.Any suggestion on cams? 400 small valve vortec heads, rockers, headers, 3000 lb car occassional towing.
Have the block inspected before boring, the 400s have a history of being thin-walled from the factory. From what I hear/read, sonic testing is on the pricey side but my philosophy is it's better to spend the money upfront and know what you have than to build it and have it disintegrate unexpectedly. Vortec heads are lift-limited in stock form. The spring retainers start hitting the valve seals at about .480 lift, IIRC. Do some research on that to make sure or ask your machinist, he/she should be knowledgable on the subject. Whatever heads you use, make sure they have the steam holes that are unique to the 400sbc. Non-400 heads can be drilled for use on the 400 block. Vortec heads use guided rocker arms. You can get guided roller rockers for use with late model heads. You can use guided rockers or convert to the traditional pushrod guide plates but not both.Vortec heads were designed for use on the 350 and may be on the small side for a 400. They will perform fine at lower rpm but may be breathing-limited for upper rpm use, say above 4500 or so. I've never had/built a 400 and have only used Vortecs on/in stock form.
To get more experienced resopnse to your questions you can also log into the forums at Chevy High Performance. Most of the people there browse here too, but that site is much more active than this one.http://www.chevyhiperformance.com/http://forums.chevyhiperformance.com/
+1 on the CHP Forum too....+1 Scott on the thin walls. The 2 Bolt 400 Blocks were the best. Be carefull on the thrust side if you are not going to be racing it every weekend. Use only .150 as an absolute minimum on the thrust sides. make sure all the steam holes line up with your head gasket. If your using a small block head. Align the gasket and if it doesn't have the steam holes as the head gasket, drill the steam holes in the head. Use the head gasket as a templete. Use a 400 head gasket only...Bob
.. The stock Vortec heads support up to 425-450HP so fine for a SBC 400 for cruising/trailer towing usage... use KB flat top or dished pistons... or some other pistons that don't have a shorter than stock 1970 SBC 400 compression height like most basic 'rebuilder' pistons do ... anywhere from a stock 196/202 to 219/229 duration cam... if going over .450" - .480" valve lifts, Alex's retainer/spring kits work without mods on Vortec heads....http://www.alexsparts.com/valve-spring-kit-sb-chevy-vortec-hi-perf-hyd-roller
to put the 3.25 inch stroke crank in the 305 block,you would need to use the 5.94 inch long  LT1 type powdered metal cracked cap con rods.you also must use the 1.43 inch compression hight [334 stroker] after market pistons.vary head gasket thickness as needed.