HELP Upgrading engine

FluoFerret

Greasemonkey
Apr 2, 2018
184
43
Luxembourg
Hello everybody!
My 350 Chevy SB just quit on me: valve stem seals leaking, burnt valves and by the looks of it, eaten valve guides and damaged valve stems.

I am currently thinking to go from a "mild performance" crate engine (that's what it is/was) up to something a little more peppered. nothing fancy, just a little more efficiency for the size.

The general idea is to go with new cylinder heads with smaller combustion chambers (660 to 64cc) and a roller cam that can make the most out of the cylinder heads. The current intake is an Edelbrock Performer EPS and on top sits an Edelbrock 650 AVS2 carb. I would love to keep them, at least the carb.

Here's the camshaft / cylinder head specs as of now:
- Hydraulic flat tappet
- Lift is .450 intake / .460 exhaust.
- Duration at @.050 is 222 degrees intake/exhaust.
- Rocker arm ratio 1,5:1
- Cylinder head type: cast iron 76cc chambers
- Valve size: 1,94 intake / 1,5 exhaust
- Compression: 8,5:1
- cast aluminium pistons (flat)

I would love to get compression up to 9,5:1 at least or even 10:1, but I wonder if this can be achived by just going down from 76cc to 64cc combustion chambers.
For the cam, I want to go with a roller cam that gives good low to mid rpm range torque. The car should be able to pull away fast, but I don't want a street dragster or a street racer that needs high RPM to achieve this.

Anyone got some good leads for me to choose the right parts? Google hasn't been much of help, since many articles are seemingly contradicting themselves. Or I am too stupid to make sense out of it... Either way, any help to get me on track is most welcome! :)
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
5,119
113
Upstate NY
What pistons are in it now? Flat, small dish, big dish?

And, what's your budget?

Heads - budget- NKB with a valve kit from Competition products, after that a set of as cast Profiler 195 or 210's, and then of course for the top of the line - AFR's. If you can swing it, then have Chad Speier sell you a set of CNC's Profiler's.


Advice - roller cam from Howards including a set of link bars - cheapest good quality stuff. Spend all the money you can on the heads, but the price range of OK, good, very good and superb heads range from $1000 to $2500. Remember, or be aware of all of the attaching parts that will be needed with a roller cam and head upgrade- i.e. rockers, pushrods, guide plates, etc. It adds up quick.

DON'T UNDERSIZE THE INTAKE RUNNER. A 210 runner is NOT, NOT, NOT too much for a street car.
 
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FluoFerret

Greasemonkey
Thread starter
Apr 2, 2018
184
43
Luxembourg
What pistons are in it now? Flat, small dish, big dish?

And, what's your budget?

Heads - budget- NKB with a valve kit from Competition products, after that a set of as cast Profiler 195 or 210's, and then of course for the top of the line - AFR's. If you can swing it, then have Chad Speier sell you a set of CNC's Profiler's.


Advice - roller cam from Howards including a set of link bars - cheapest good quality stuff. Spend all the money you can on the heads, but the price range of OK, good, very good and superb heads range from $1000 to $2500. Remember, or be aware of all of the attaching parts that will be needed with a roller cam and head upgrade- i.e. rockers, pushrods, guide plates, etc. It adds up quick.

DON'T UNDERSIZE THE INTAKE RUNNER. A 210 runner is NOT, NOT, NOT too much for a street car.

Pistons are flat

Budget for the heads is 1500. The reason here is the shipping cost and import tax that will be added. Unless I can import them via a supplier that gets all of it via ship-container once or twice a year, thus having really low shipment prices.
Haven't set a budget for the cam yet. Too many variables, but I might increase it, since the german company "Mahle" has its factory around here, and since they manufacture pistons for chevy small blocks, I might be able to order from them directly and "win" on the shippment/tax.
I have yet to take out the pistons/crankshaft, but I hope they have no apparent damage. The cylinder walls still show the criss/cross honing pattern, and there is no scratches visible. but I will have to measure it out to be 100% sure.

Another question I keep asking myself if I shouldn't just buy a new "BluePrint" crate engine that has the specs I wish for. But then again, import and transport costs will push the engine to 10000K :( Plus, I see mixed reviews for BluePrint engines.....
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
5,119
113
Upstate NY
BluePrint = good. $10K = bad, haha


Not sure of the tariffs, but these are more than a functional head that are budget friendly.
 

86LK

Royal Smart Person
Jul 23, 2018
1,196
113
Hello everybody!
My 350 Chevy SB just quit on me: valve stem seals leaking, burnt valves and by the looks of it, eaten valve guides and damaged valve stems.

I am currently thinking to go from a "mild performance" crate engine (that's what it is/was) up to something a little more peppered. nothing fancy, just a little more efficiency for the size.

The general idea is to go with new cylinder heads with smaller combustion chambers (660 to 64cc) and a roller cam that can make the most out of the cylinder heads. The current intake is an Edelbrock Performer EPS and on top sits an Edelbrock 650 AVS2 carb. I would love to keep them, at least the carb.

Here's the camshaft / cylinder head specs as of now:
- Hydraulic flat tappet
- Lift is .450 intake / .460 exhaust.
- Duration at @.050 is 222 degrees intake/exhaust.
- Rocker arm ratio 1,5:1
- Cylinder head type: cast iron 76cc chambers
- Valve size: 1,94 intake / 1,5 exhaust
- Compression: 8,5:1
- cast aluminium pistons (flat)

I would love to get compression up to 9,5:1 at least or even 10:1, but I wonder if this can be achived by just going down from 76cc to 64cc combustion chambers.
For the cam, I want to go with a roller cam that gives good low to mid rpm range torque. The car should be able to pull away fast, but I don't want a street dragster or a street racer that needs high RPM to achieve this.

Anyone got some good leads for me to choose the right parts? Google hasn't been much of help, since many articles are seemingly contradicting themselves. Or I am too stupid to make sense out of it... Either way, any help to get me on track is most welcome! :)
this is the CURRENT specs of your engine? some possible methods for achieving higher compression on your heads would be:
-thinner head gasket
-shave the heads
-increase camshaft duration to allow more filltime on the intake stroke
-change pistons

this guy has been writing for years for multiple different magazines and knows what he is talking about...
 

abbey castro

G-Body Guru
Oct 31, 2015
805
93
Harker Hts TX
For what its worth (FWIW):

I'm running a GM Crate ZZ4. 355 HP plenty of power. Unless you are willing to make a puzzle of parts try and work together, that everyone has ideas on, don't!
 

CopperNick

Royal Smart Person
Supporting Member
Feb 20, 2018
2,387
113
Canada
Too bad Britain is no longer part of the EU, you could have made the trip over there via the Chunnel or the Ferry and checked out a couple of their swap meets. Never know what could turn up at one of those and the import price to the continent would likely be a lot cheaper than an air freight ticket for a completely crated and palletized engine; that method being the only safe way to ship international, too many ham handed forklift jockeys wearing unapproved safety helmets with Achmed written on their coveralls.


Nick
 

ck80

Comic Book Super Hero
Feb 18, 2014
4,649
113
Too bad Britain is no longer part of the EU, you could have made the trip over there via the Chunnel or the Ferry and checked out a couple of their swap meets. Never know what could turn up at one of those and the import price to the continent would likely be a lot cheaper than an air freight ticket for a completely crated and palletized engine; that method being the only safe way to ship international, too many ham handed forklift jockeys wearing unapproved safety helmets with Achmed written on their coveralls.


Nick
Tariffs being what they are it's worth imitating a non-fuctional Hurst hairy olds to drive to the swap meet using pretty painted but junk parts. Then put good stuff in place of the junk for the ride hone and pay no tariffs, throwing the ditched stuff in the trash or on a table with a sign free if need be before driving home
 
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spidereyes455

G-Body Guru
Mar 6, 2013
717
93
Northeastern PA
Generally just going from a 76cc head to a 64cc head alone should net you close to one full point of compression ratio. Thicker than stock head gaskets will rub out some of the overall gain. But finding all the required measurements and using an online calculator will give you more exact results
 
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Reactions: 1 user

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