How to make more cubic inches

[400hp_76]

I posted one or two threads about more cubic inches. I have been told that you can get 427 cubic inches / or 426 ci out of a 400 small block with the proper modifications. i want to get more ci out of the small block because of weight reduction reasons. Price is also a concern of mine, but i already have the heads for a small block and manifold, you name it i have it . all i need is the short block. A few have replied and helped me out a lot with my older threads. any of your comments will help. thanks, "T"

 

[JohnZ]

Can't give you any specifics, but yes, it's possible - with a LOT of custom machine work and very expensive parts. Not a "budget" project, to be sure.

 

[Jack]

T (400hp_76):
JohnZ 's overview is right on. One of our community moderators here (Ken) is building a big small block for his C4. Ken's saga is detailed in many posts on CACC's C4 forum. At minimum, you're gonna need a stroker crank, expensive rods, expensive pistons and probably a small base circle cam (often an expensive roller setup), great flowing heads (often expensive aluminum) ... and probably extensive/expensive machining & clearancing of your block. Hope you also have adequate transmission, differential, brakes & tires to harness the beast. It's all doable ... if your wallet can stand it. Check Ken's posts.


http://corvetteactioncenter.com/forums/showthread.php?s=&threadid=6157&perpage=15&pagenumber=6

http://corvetteobsession.homestead.com/files/html/corvette.html

JACK:gap

 

[400hp_76]

Jack,

I had a reply earlier on this topic where the work has already been done for you . the short block cost 3700$ which is not bad at all. One of the members on here sent it to me.(Bullitt)-"Super Gorilla small block. It can be had in 420 (.030 over) or 426 cubic inches (.060 over). The bore is 4.125+, 3.875 stroke and a 5.700 connecting rods. This is with a 400 block and a custom ground 5140 forged crank.The total is $3700 for a short block assembly". As for the great flowing heads. I can have my set of dart iron eagle heads worked to be the proper setup with whatever specs i want my cam to have. As for the cam i was planning on using a roller type cam. comments. thanks, T

 

[inferno-vette]

I've seen a SB with 434 ci 4.155 bore and 4.0 stroke. More than this I don't know!
Paul

 

[maxrevs85]

Would consider useing a regular Flat tappet hydraulic cam vrs a roller. Reliability and longevity. Rollers will not take the 0ver 6000 rpm s for long. Its not will they fail its when. And i strongly recomend having the splayed main caps if your going over 450HP. Also dont go with the short rods (5.7) . use aleast a 6"or more , less angle and less strain and wear.

 

[400hp_76]

I thought that most new vehicles have roller setups and most of them arent dropping like flies. You have to admit that rollers do make a lot of hp, but more than likely i will stick with a normal cam. I have heard your point before and its a good one. What would be a good set up for the 426 sb that i will be building this summer. have having been looking over good combos. what lift cam and what duration-int valve and exh. valve sizes and carb sizes. I am looking for combinations that have been used before that make a lot of hp, so it will not be much guessing when i go to buy the cam and have the heads ported to a larger size.

 

[AKRAY4PLAY]

406's and 426's are very common with old school hot rodders. they are great motors because they have the cubes for making power, yet still a small block for the weight aspect. there are tons of little things to considder when you decide to use a small block 400 for a build!! be sure you have steam holes drilled in your heads to cool the siamesed cylinders. if you build a 400 over 600hp, you will be smart to have the block machined for installing water jets, that are fed from the waterpump, and inject into the side of the block at all cylinder juctions, six in all. splayed mains are a must, straight four bolt mains actually weaken the block. the bolts usually go through the casting fault of the main bearing webbing. there are lots of tricks to setting an old block up, and they all cost money. if you decide to build up an old 400, start with a two bolt main block that doesn't have any core shift and ample cylinder wall thinkness. i built a hot 406 and spent $12,000 to get it right. looking back i should have bought a brand new goodwrench 400 block with splayed mains and siamesed cylinders. the block is ready to go from gm performance for around $2400. the coolest thing with the new block is that the main bearings are priority oiling. it is easy to build a 426 with this block, and even possible to build a 454, but not many mortal men have that kind of cash flow. there are lots books on building 400's, the $40 i spent was very informative and enlightening. my advice is research heavily before you leap into a sb400. best of luck, brian

 

[400hp_76]

Brian,

I have not recieved my P.A.W. magazine yet, but i have been told that there is a short block that is sold for 3,700$. It is a 400 small block set up as 426 cubic inches. It is called a super gorilla small block. Whether or not it has splayed mains im not sure. I will have to look into that. I was certain that i was gonna have to do all the stuff that you said. I t was just a matter of how to go around the big bucks. Thanks for the info. It helped reasure me of what i am gonna have to do to make this a beast. I wish i could get one more cubic inch out of it. haha. ahhhh the prestige of a 427.

There is something about wearing black. It instantly conjures up thoughts like "If you want to mess with me, you'd better take an inventory of your abilities first.

 

[Jack]

T (400hp_76): Brian offers us good advice.

Following applies to strokers, whether 350 or 400 block. Roller cams typically have a smaller base circle than a "normal" flat tappet cam; so a roller cam can have a higher "effective" lift while the overall height of lobe is less than found in "normal" cam; the roller cam's billet steel material is strong enough to help prevent breakage in a cam having an overall smaller diameter than "normal" iron flat tappet cam. An increased stroke will bring factory-type 5.7" (350) rods in contact with lobes of even a mild "normal" cam :eek; the problem escalates as stroke lengthens and/or lobe heightens. Some cures are: (1) grinding away big-end rod material near where top of rod bolt is on factory-type 5.7" rods "aka cam-clearancing" , (2) acquire aftermarket rods that have cap screws instead of bolts , (3) use shorter 5.565" 400 rods ... naaahh, (4) acquire an aftermarket block having a "raised cam" and longer tc set or gear drive ... this raises the cam somewhat above factory , (5) acquire a small base circle cam ... typically a billet steel roller setup , (6) some combination of the five.

Assembling a REALLY BIG sbc stroker???: look to use aftermarket rods with cap screws (aka 3-D H-Beam) and a billet steel roller cam setup. For street use, I suggest you do not go more than 30 overbore (4.155") on a GM passenger car/truck 400 block.

Within a vette 350 block, I'm assembling a very mild 388 with 4.030 bore & 3.8" stroke. My normal flat tappet cam with only .460" lift required cam-clearancing of factory-type 5.7" rods. Also, the block required clearancing at cylinder bases and oil pan rails ... even though this is a relatively mild & small stroker.
JACK:gap

 

[400hp_76]

All great advice. If i go with anything i will go with the block from powerhouse automotive warehouse. Of course i will look more into it, but it sounds great. I am not rushing into anything. I already have a beast of a 357. This will be a summer build and then a winter swap. Whatever i do i will make sure that i have all the components dont correctly and installed properly. I dont do anything half...... . Thanks for all the info and continue sending your comments. every little bit helps. thanks, T

 

[maxrevs85]

I would like to say that I'm not against roller cams, they do make horse power .I just know that they are not a good deal for engines that plan on running over 6000 rpms . The lifters are the problem . they are heavy and tend to float sooner then a flat tappet cam. And they are prone to breaking, Its the bearings .And they have a low rpm idle problem with oiling also. If you talk to the people at comp cams and tell them what you are doing ,they can have a specific grind for you that will make the HP that you want for alot less in a flat tappet hyd vs the cost and and really no significant advantage with the Roller. Yes all the new cars come with rollers but they are not driven at high rpms. The longer rods though are a better deal ,they locate the piston pin higher and reduce the rod angle which reduces the stress of the whole assembly. I'm having a 383 built right now . I also have a another 383 with aDart block and AFR heads with Jesel rockers and steel crank and rods etc.....635 hp on the dyno. It has a solid roller cam. I twist that one 72 to 7500 rpms....:eek ...what a rocket .........by the way its for sale....brand new and dyno time only.

 

[Bullitt]

Super Gorilla Info

From Performance Automotive Warehouse (PAW):

Block: 400 Chevy fully machined and prepared for high performance use including the installation of steel billet 4 bolt caps on the three center mains. Each block is bored oversize and power honed for moly rings, dry decked and finished with new cam bearings, brass freeze plugs, screw-in oil galley plugs and a fresh coat of high-temp Chevy orange. Custom bearing spacers are included with each block.

Crankshaft: Custom ground forged 5140 crank. Polished with oil hole chamfered and heavy duty rod & main bearings.

Rods: High performance 5.7" long connecting rods shot peened, magnufluxed, fitted with chrome moly rod bolts for maximum strength.

Pistons: Custom made forged racing piston in the compression of your choice.

Camshaft: Your choice of solid or hydraulic cams from Super Stock Industries.

Timing Chain Set: Double-roller

Rings: Moly top ring with stainless oil ring.

Balanced for maximum performance.

Options: Steel Connecting rods and/or roller camshaft.

PAW sells at least 19 different short/long block Chevy combinations. Plus 9 Ford combos and 440 Chrysler. The one that I dream of is the 427 Ford from a punched out 351 Windsor that I want to put into a 1967 Fastback 'Stang. I think I need to finish working on my Vette first.

--Bullitt

 

[400hp_76]

FORD?????

What are you doin mentioning ford. haha. I am just kidding. I have had my eye on a old mach one that is just collecting pine needles. I can picture it in my mind every time i see it. The one car I have wanted before the company even became popular was a Factory Five 427 roadster or daytona coupe kit. I had thought about selling my corvette when it caught on fire. I was so frustrated with the corvette, but i couldnt sell it becuase of all the time and effort i put into it with my dad. I am building a nice size shop with a pit and a lift in the ceiling this summer. I have so many ideas running through my head about what to do. I thought about finding a wrecked c-5 and using the suspension set up and frame/possibly the drivetrain, but for cost reasons just stick with the sbc and a late model camaro 5 speed or 6. Take a c-3 body and retro fit it. or something along those lines. I want something just totally raced out. We will see how it all goes. and Bullitt i gotta get a PAW magazine and some money. thanks, T