I got a sbc 350 block .40 over with 3.5 stroke crank 64cc/210cc aluminum heads 1.6rockers wondering before I buy more stuff what pistions/rods and cam people could suggest me I'm thinking of getting 6 in rods with 5cc flat tops not sure on the cam tho thinking I want to get around 650lift for flow and enough duration to rev out to 7-8krpms. Hyd or solid im cool running eighter. Looking for forged stuff to go with the build and roller cam not flat tappet. Motor will have a 150shot nitrous
Jonathank20
Sbc parts spec questions
1 reading
7500 rpm solid roller 358 cube engine could make 550 hp N.A. Might want to build a 427 if you plan on spending that much money? THe only difference in costs will be the big bore block. The after market block will survive better than a stock GM block making 550 (plus 200 hp NO2). The 427 will net 650 hp N.A. ( plus 200 hp NO2)
2old?
if it costs $2500 more for 80 cubic inches (120 hp more) for a block that is not at risk of breaking relative to a factory block that comes into question after 500 hp.
Note: op wants to rev over 7k, and I would assume wanting to make power to redline. My engine is sub 7k and over 600 hp so I bought a little m for my application. I got mine for $2200 years ago
if it costs $2500 more for 80 cubic inches (120 hp more) for a block that is not at risk of breaking relative to a factory block that comes into question after 500 hp.
Note: op wants to rev over 7k, and I would assume wanting to make power to redline. My engine is sub 7k and over 600 hp so I bought a little m for my application. I got mine for $2200 years ago
I spray quite a bit more on 92oct pump gas with my stock 010 block 355. 42lb Scat F43 with 1492g bobweight. I used these pistons on aluminum rods with an un-decked block...
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251/261 114 .650"
340cfm Brodix 11RI sprint car heads that originally toured the country with Steve Kinser
Built it in 2016. Regularly gets spun well past 8k in my street/strip car, only maintenance is changing oil/filter and a yearly check of the valve adjustment.
Here's a link with info on the build... http://grannys.tripod.com/20102.html
Grant
251/261 114 .650"
340cfm Brodix 11RI sprint car heads that originally toured the country with Steve Kinser
Built it in 2016. Regularly gets spun well past 8k in my street/strip car, only maintenance is changing oil/filter and a yearly check of the valve adjustment.
Here's a link with info on the build... http://grannys.tripod.com/20102.html
Grant
A 6 inch rod and matching piston is a good combination. The wrist pin should be floating rather than pressed this will use pin retainers which most builders prefer Circlips which are a tightly wound spring steel spiral simple and foolproof to install but a super bear to remove. The other choice is Tru Arc clips these work well and are easier to remove but attention needs to be paid as to their direction of installation where they have different shape edges rounded on one side and sharp on the other, installation requires the sharp edge face out as forces on the pin can push the rounded edge over the retaining lip of the pin bore. In any event floating pins offer one more point of movement should high heat on the piston result in the pin becoming bound in the piston’s pin bore and of course they allow R&R of the piston and rod without a press or destruction of the piston.
Attention needs to be paid to the clearance space of piston to block deck. This affects gasket selection and the mechanical squish/quench clearance. Typically GM specifies .025 inch at TDC for piston crown to block deck. With iron head’s it’s easy to use thin shim head gaskets to get the sum of gasket thickness and crown to deck clearance down to the desired .040 inch range to minimize detonation. The case with aluminum head’s is more difficult as thin shim gaskets abrade the head at the fire ring so a composite gasket or a copper sheet with O rings is a less wearing solution to the gasket but the additional thickness of these gaskets drops the anti-detonation qualities of the tight squish/quench clearance. To get around the abrade wear issues with thick head gaskets thusly requires that either the block be zero decked and or a raised crown piston be used. These dimensions also effect compression ratio so this can drive on piston and head selection, you have to do the math ahead of buying parts as it’s easy, especially if your going to boost the motor, to get into trouble here. Since you already have 64 cc chamber aluminum head’s you’re going to half to dink around with the pistons to get the whole into a zone that doesn’t make scrap iron out of the motor. Your selected power level of 500 to 550 is on the upper limit of a stock block the slightest foul will have your expensive build being picked up with a broom. Another place that needs your attention is piston skirt clearance to the counter weights when each piston is at BDC.
Cam selection with any kind of power boost needs more exhaust help. That leads to more than typical duration and or lift, a larger valve, better exhaust side porting, larger than typical headers and exhaust system, this is simply because there is more combustion product that has to be removed from the engine. This, also, emphases spending more money on exhaust valves for those made from better materials that better withstand the much increased heat and chemistry of combustion byproducts. Titanium however requires special seats, guides, retainers and locks, moving to Ti is a lot more expense than just the valves.
The stock block is most worrisome. The beef in a stock part is based on having enough fatigue strength to allow the part to age in a reasonable life span the customer finds acceptable. This boils down to the structure resisting ordinary stress for a period of time. Building a high performance engine using stock parts is putting higher stress into those parts the payment of which is reduced lifecycle. A fair rule of thumb is a 500 mile race such as Daytona removes about the same lifespan from a block as 100,000 street miles of a daily driver. So when you start taking big power numbers out of stock block it’s design life span gets used up mighty quickly. Add to that thought you’re probably not starting with a virgin block so some X amount of its design life has already been removed from its structure. At point forty over probably adding a fill of Tuff Block up to the soft plug line would be helpful. Many if not most boosted engines fail the mid bore wall so strength in this area is most helpful. The thing you can’t beef up much is the bearing bulkheads which at high power levels these tend to fail through the cam bearings and pull apart with your gold plated 4 bolt main cap still attached. In your case I’d consider adding a main bolt girdle these help spread the loads of any one main applied to its bulkhead across all the bulkheads. Another is that aftermarket splayed 4 bold caps move the outer bolt load into the join between the pan rail and the bulkhead so the loads are shared over a larger area of the block as is found with the typical inline bolt pattern.
Balance and damping are really important on the crank. This is especially true in the center three mains where the lack of counterweights to either side of the center main cap puts a bending load on the crank that these center 3 mains are absorbing (thus the real reason for 4 bolt mains here). So balls on balancing by a pro balance shop goes a mighty long way in keeping the middle of the crank and block together. This is especially a concern with lightweight cranks. These are nice to result in a crank that spins up fast but if your not careful with your part balance these cranks are fast to fail. It’s one thing if you use these in a money machine it’s something else if you expect more than a race or two out of the crank. Everything relates to everything else you can’t just go cherry picking one part at the ignorance of its affects on the others. Something to check is the quality of the thrust surface of the crank. This is a problematic area for everybody making cranks and Eagle has had their share. Damping on the front of the crank always critical and not often considered so either by the OEM’s or part time performance engine builders. These usually get by on minimalist mixes of hubs and rings bonded together with a rubber interface with a lot of assumption that this is sufficient. But given this object is there to dampen the twists in the crank that come and go on each crank pin as power is applied then released on every fourth stroke of each piston. Once again as power generated goes up the twist and unwind forces applied go up in amount and if you wind the engine out also in frequency. This is hard on the mains especially the number one where vibratory moments are being reacted into the damper and undamped forces not resolved by the damper are being reflected back into the crankshaft. The typical failures here are either the crank snout snapping off or the number one main gets carved out followed by a loss of oil pressure in the engine followed by rod bearing failure usually stating on the number one crank pin or frequently as a failure on the thrust main taking out the rod bearings on the fourth pin journal.
The message here is not only do you need to select parts that make power but you also need to select parts that keep the motor together at the power being made. It’s an expensive feedback loop. Expensive in first purchase parts and processes or expensive as lesser than required parts are reduced to a pile of junk parts. Many times even the expensive parts are reduced to junk as well it’s hard to build high power engines that stay together.
Bogie
Attention needs to be paid to the clearance space of piston to block deck. This affects gasket selection and the mechanical squish/quench clearance. Typically GM specifies .025 inch at TDC for piston crown to block deck. With iron head’s it’s easy to use thin shim head gaskets to get the sum of gasket thickness and crown to deck clearance down to the desired .040 inch range to minimize detonation. The case with aluminum head’s is more difficult as thin shim gaskets abrade the head at the fire ring so a composite gasket or a copper sheet with O rings is a less wearing solution to the gasket but the additional thickness of these gaskets drops the anti-detonation qualities of the tight squish/quench clearance. To get around the abrade wear issues with thick head gaskets thusly requires that either the block be zero decked and or a raised crown piston be used. These dimensions also effect compression ratio so this can drive on piston and head selection, you have to do the math ahead of buying parts as it’s easy, especially if your going to boost the motor, to get into trouble here. Since you already have 64 cc chamber aluminum head’s you’re going to half to dink around with the pistons to get the whole into a zone that doesn’t make scrap iron out of the motor. Your selected power level of 500 to 550 is on the upper limit of a stock block the slightest foul will have your expensive build being picked up with a broom. Another place that needs your attention is piston skirt clearance to the counter weights when each piston is at BDC.
Cam selection with any kind of power boost needs more exhaust help. That leads to more than typical duration and or lift, a larger valve, better exhaust side porting, larger than typical headers and exhaust system, this is simply because there is more combustion product that has to be removed from the engine. This, also, emphases spending more money on exhaust valves for those made from better materials that better withstand the much increased heat and chemistry of combustion byproducts. Titanium however requires special seats, guides, retainers and locks, moving to Ti is a lot more expense than just the valves.
The stock block is most worrisome. The beef in a stock part is based on having enough fatigue strength to allow the part to age in a reasonable life span the customer finds acceptable. This boils down to the structure resisting ordinary stress for a period of time. Building a high performance engine using stock parts is putting higher stress into those parts the payment of which is reduced lifecycle. A fair rule of thumb is a 500 mile race such as Daytona removes about the same lifespan from a block as 100,000 street miles of a daily driver. So when you start taking big power numbers out of stock block it’s design life span gets used up mighty quickly. Add to that thought you’re probably not starting with a virgin block so some X amount of its design life has already been removed from its structure. At point forty over probably adding a fill of Tuff Block up to the soft plug line would be helpful. Many if not most boosted engines fail the mid bore wall so strength in this area is most helpful. The thing you can’t beef up much is the bearing bulkheads which at high power levels these tend to fail through the cam bearings and pull apart with your gold plated 4 bolt main cap still attached. In your case I’d consider adding a main bolt girdle these help spread the loads of any one main applied to its bulkhead across all the bulkheads. Another is that aftermarket splayed 4 bold caps move the outer bolt load into the join between the pan rail and the bulkhead so the loads are shared over a larger area of the block as is found with the typical inline bolt pattern.
Balance and damping are really important on the crank. This is especially true in the center three mains where the lack of counterweights to either side of the center main cap puts a bending load on the crank that these center 3 mains are absorbing (thus the real reason for 4 bolt mains here). So balls on balancing by a pro balance shop goes a mighty long way in keeping the middle of the crank and block together. This is especially a concern with lightweight cranks. These are nice to result in a crank that spins up fast but if your not careful with your part balance these cranks are fast to fail. It’s one thing if you use these in a money machine it’s something else if you expect more than a race or two out of the crank. Everything relates to everything else you can’t just go cherry picking one part at the ignorance of its affects on the others. Something to check is the quality of the thrust surface of the crank. This is a problematic area for everybody making cranks and Eagle has had their share. Damping on the front of the crank always critical and not often considered so either by the OEM’s or part time performance engine builders. These usually get by on minimalist mixes of hubs and rings bonded together with a rubber interface with a lot of assumption that this is sufficient. But given this object is there to dampen the twists in the crank that come and go on each crank pin as power is applied then released on every fourth stroke of each piston. Once again as power generated goes up the twist and unwind forces applied go up in amount and if you wind the engine out also in frequency. This is hard on the mains especially the number one where vibratory moments are being reacted into the damper and undamped forces not resolved by the damper are being reflected back into the crankshaft. The typical failures here are either the crank snout snapping off or the number one main gets carved out followed by a loss of oil pressure in the engine followed by rod bearing failure usually stating on the number one crank pin or frequently as a failure on the thrust main taking out the rod bearings on the fourth pin journal.
The message here is not only do you need to select parts that make power but you also need to select parts that keep the motor together at the power being made. It’s an expensive feedback loop. Expensive in first purchase parts and processes or expensive as lesser than required parts are reduced to a pile of junk parts. Many times even the expensive parts are reduced to junk as well it’s hard to build high power engines that stay together.
Bogie
Part of Bogie's inquiry in post #3 contains the single most vital question and, from what I can tell, it has yet to be answered. For what purpose is this build? The application is HUGE when it comes to getting specific information and advice. Some of these things may be unknowns at present but these things are the start of putting together an effective combination. Answer what you can:
Do you have a vehicle already? If so, what is it?
What rear end and gear ratio?
What transmission and torque converter?
What type of driving will you mainly do? (If you build for the majority of what you're doing, you will be happier overall).
What is your budget for the whole project? (If you have $10,000 to spend and $8,000 goes in the engine...it doesn't leave enough for other needs).
Do you have a vehicle already? If so, what is it?
What rear end and gear ratio?
What transmission and torque converter?
What type of driving will you mainly do? (If you build for the majority of what you're doing, you will be happier overall).
What is your budget for the whole project? (If you have $10,000 to spend and $8,000 goes in the engine...it doesn't leave enough for other needs).
Since you mentioned to Moosecountry that you might go to an aftermarket block later etc., and the concerns that have been expressed with 500+ hp in a factory block, I think you should consider building this motor to be in the <500hp range, and then go for 550+ if you decide to build a big CI sbc in the future.
I've had builders tell me the same thing. that 500hp would be the absolute max they'd use a factory block for... but then you should have the block sonic tested to make sure that it would even handle that.
I had bought a factory 4-bolt block that was .040 over, and it sonic tested bad. The builder that tested it said he wouldn't use if for anything other than a daily driver putt-putt motor.
Especially if your block is an old block, you're going to want to make sure it's good for what you want to do.
I've had builders tell me the same thing. that 500hp would be the absolute max they'd use a factory block for... but then you should have the block sonic tested to make sure that it would even handle that.
I had bought a factory 4-bolt block that was .040 over, and it sonic tested bad. The builder that tested it said he wouldn't use if for anything other than a daily driver putt-putt motor.
Especially if your block is an old block, you're going to want to make sure it's good for what you want to do.
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