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2 or 4 bolt block?

To get lift number with 1.6 rocker, divide lift number by 1.5, then multiply by 1.6.

Edmund,

like others have said, the only thing a 4 bolt main is for mainly racing. if your winging it up 7000+ rpm then by all means a 4 bolt main block would be beneficial BUT on the other hand then you wouldn't have the streetability of Hydrualic rollers either unless you spend more money to get the lifter bore resized (i think)

if you want the strength get the mains splayed. this means the 2 bolts that hold the main cap on is set at a 45 degree angle (not that aggressive but you get the picture) and can withstand alot more rpm and torque so it won't lift the cap off the crank and spin a bearing. this setup is a little stronger.

IMO don't get cheap on the crank, rods, or pistons. you can get good rotating assemblies for 1500+ about 700 more you could have the same stroker kit and not a 355 kit with block work.

CHEVY 350 HYPEREUTECTIC PISTON 'ECONO' ENGINE KITRK350EH$ 699.00Have Rotating Assembly "Computer Balanced"$ 200.00
  • NEW FEDERAL-MOGUL HYPEREUTECTIC FLAT TOP PISTONS, 10.0 : 1
  • NEW EAGLE "SIR" 5.7" I-BEAM CONNECTING RODS W/ ARP WAVELOCK BOLTS
  • NEW SCAT CAST STEEL 3.48" STROKE CRANKSHAFT
  • NEW SEALED POWER MOLY PISTON RINGS
  • NEW CLEVITE 77 ROD & MAIN BEARINGS
CHEVY 350 I-BEAM "SUPER COMP KIT"RK350SC$ 1549.00Have Rotating Assembly "Computer Balanced"$ 200.00
  • NEW FEDERAL-MOGUL FORGED DOMED PISTONS, 11.5 : 1
  • NEW EAGLE 5.7" I-BEAM BUSHED CONNECTING RODS W/ ARP WAVELOCK BOLTS
  • NEW EAGLE 3.480" STROKE, 4340 FORGED NITRIDED STEEL CRANKSHAFT
  • NEW SEALED POWER MOLY PISTON RINGS
  • NEW CLEVITE 77 "H SERIES" RACE ROD & MAIN BEARINGS
CHEVY 350 "383" STROKER HYPEREUTECTIC PISTON ECONO KITRK383E$ 899.00
  • NEW FEDERAL-MOGUL HYPEREUTECTIC FLAT TOP PISTONS, 10.25 : 1
  • NEW EAGLE "SIR" 5.7" I-BEAM CONNECTING RODS W/ ARP WAVELOCK BOLTS
  • NEW SCAT CAST STEEL 3.75" STROKE CRANKSHAFT
  • NEW SEALED POWER MOLY PISTON RINGS
  • NEW CLEVITE 77 ROD & MAIN BEARINGS
  • For externally balanced style Harmonic balancer & Flywheel only.
CHEVY 350 "383" STROKER FORGED PISTON I-BEAM "SUPER PRO KIT"RK383SP$ 1599.00Have Rotating Assembly "Internally" Computer Balanced$200.00
  • NEW FEDERAL-MOGUL FORGED FLAT TOP PISTONS, 10.5 : 1
  • NEW EAGLE "SIR" 5.7" I-BEAM CONNECTING RODS, W/ ARP WAVELOCK BOLTS
  • NEW EAGLE "ESP" 4340 FORGED NITRIDED STEEL 3.75" STROKE CRANKSHAFT
  • NEW SPEED PRO PLASMA MOLY PISTON RINGS
  • NEW CLEVITE 77 "H SERIES" RACE ROD & MAIN BEARINGS
no difference except getting your block worked for the 400 crank if you go stroker. http://www.cdpautomachine.com/ecatalog/rotating%20assemblies.html

*I just did a google search and pulled this site up as i've been looking myself*

IMO if you want to drive the car and leave it as it is then go with the scat cast crank with hypereutectic pistons but if you want to play with it because your not happy with the power or want more power such as adding a bigger cam and or nitrous then go with the forged H beam setup. the cast stuff will hold easy 6500 rpm sustained and winging to 7000 rpm on occasion. Forged you can wing 7000+ as long as your valvetrain is good :D

Cam selection should be 2teen range duration .480" lift 112 lobe seperation. with the 1.6 RR's it comes to total lift of .512" which is a good streetable cam for a 350. then your setup really don't need the bigger heads and such either if you look at cam size that way. my guesstimation would be in the 320 rwhp and 410 rwtq. with a 228 .525 112 lsa on 1.6 RR's would see a total lift of .560" which in return will use the heads, Big Mouth intake, AS&M Runners, and ported plenum to it's full ability and you'd see most likely closer to 380 rwhp and close to 500 rwtq. if you go small cam you can always change it later or juice it if you like the streetability but get the good kit if you would like to play with it more.

that pretty much sums it up and those are the questions you want to ask yourself. if you just want to build it and drive it or know you got something under the hood to trounce new C6's :D
 
Edmond said:
You get slightly more lift. I wish I had my guide handy because you multiply the 1.6 by another number to determine lift. If you stuck with the 1.52, you would multiply the 1.52 to get the lift of that. I'll try to dig it up.

In order to get actual valve movement, you multiply the cam lift by the rocker ratio.
ex. if the intake cam lift is .310 and you have 1.5 rocker arms:
.310x1.5=.465 intake valve lift.
This is pretty basic engine component information. I would hope that anyone who is building/rebuilding an engine would know this and other basic yet important engine facts. If you do not, the first step should be to become educated in ALL aspects of the craft. A good power engine (or any engine for that matter) should not be built by on-the-job training. IMHO, the key to successful engine building is in the details. AND, there are LOTS of little details to be aware of.
Depending on the engine/heads used, changing from 1.5 to 1.6 rocker arms might require clearancing work to the pushrod area on the heads and/or different length pushrods. If you are using roller tip rocker arms, it is important to keep the roller positioned directly in the middle of the valve stem. There is no rule which says you must use the same ratio rockers throughout the entire engine. Some rocker arm sets even include eight 1.5's and eight 1.6's.
Dual pattern cams have a different lift for the intake and exhaust. Single pattern cams have the same lift for intake and exhaust.
Good luck with your project.
Terry
 
That is what i am doing to my 84 this winter 350 to a 383 these men at this site are bulding it for me they are right up the street from me will let you know how it goes will have the motor back in a week or two http://www.cdpautomachine.com/engines/chevy383_425hp_longblock.htmlWELL GOOD NEWS got my 383 back and in to been breaking her in too .This moter is ausume it pussing 525 hp and 500lb tork too turns the tires in all gears just put your foot into it and she will light it up ,need bigger tires lol.she goes 0 to 100 a lot faster then before And the sound is incrdible So now i have a corvette that puts out as much horse power as a new one and is real fast here are some pic well get back after the break in
knower57@hotmail.com
http://www.msnusers.com/knower57@hotmail.com
 
Keep us updated on the motor rebuild....If it was me I would look for a four bolt main small block 400 out of a truck and work from there.....they can be stroked out to 427 by changing the crank and knotching the block... but boy do they drink the gas..

Mike
 
I_R_DA_ONE said:
If it was me I would look for a four bolt main small block 400 out of a truck and work from there.
That's what I did Mike, but I used a two bolt main truck block for 417 cid. ;)
 
I_R_DA_ONE said:
Keep us updated on the motor rebuild....If it was me I would look for a four bolt main small block 400 out of a truck and work from there.....they can be stroked out to 427 by changing the crank and knotching the block... but boy do they drink the gas..

Mike
I read in Hot Rod or Car Craft a couple months ago that if you are going to build a 400 block you want a 2 bolt. they said that the 4 bolt blocks have weaker main bearing webs because when they added the extra bolts they didn't beef up the web thickness and they are prone to breaking when stressed before the 2 bolt will let go. I think I'd ARP main stud a 2 bolt.

Tom
 
Edmond said:
When did GM go with the 4 bolt blocks?

Is a 2 bolt adequate for regular street driving?
I would say a 2 bolt would be just fine- just as long as you aren't pushing more than 400hp/400tq and spining over 6k.
 

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