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  #46 (permalink)  
Old 07-14-2019, 01:05 AM
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Quote:
Originally Posted by Onepieceatatime7 View Post
So, just curious what kind of HP you would ballpark on my setup as my goal is 400+

Balanced shortblock .40 over zero deck
Edelbrock E street heads
Roller rockers
MSD Box , coil and dizzy
Shorty headers
Weiand single plane intake
Holley 650 DP
268H cam
10.5:1 scr

I had to use the Weiand and shorty headers for clearance.....

And yeah that lock down is a POS. Broke pretty easy last night when I tried to bend the forks.

There is general formula to make a 375 to 420 hp Gen I or Gen II, 350 SBC. It's been around I guess since the release of the L31 Vortec head on production engines since 1995. there's some flexibility in specific part choices from different sources but the core is quite simple.


- Comp XE268H cam or something from somewhere with comparable specs. and spring kit.



- GM HEI with an MSD module.


- D dish or flat top pistons are a nice addition but factory round dish especially with a good head works just fine.


- An intake with capabilities like the Edlebrock Performer RPM. No exhaust heat or EGR.



- A carb or fuel injection capable of 650 to 750 CFM. The 750 makes this a no brainer, but you can get there on a 650. 600 to 650 probably good for under 400 without too much hassle, but need to be a pretty sharp tuner to get over the 400 barrier.


- Short tube headers are going to be under 400 hp, pretty much that is just the way that is. Long tubes in the 1-5/6ths to 1-3/4tr range are needed to manage the gas flows and work the siphon magic in the collector.


- 1.6 rockers help period, certainly rollers on 7/16ths studs are real stable at tracking the lobe profile. here sits the question of self guiding or pushrod guiding. Self guiding is a no brainer, you bolt 'em on, adjust the lifter preload and go, they adjust to but do not fix misalignments between valve train part positions and only cost a few top end revs doing it from their slightly heavier ends and uncorrected alignments in the valve train. On the other hand unless you blueprint all the dimensions from the cam to the valve you can't actually realize any benefit from pushrod guiding except for a few grams lighter out on the rocker tip.


- Heads, whew where to start:


-- At around 9.5:1 compression these heads will perform in this manner. For the street there really is no need for more compression than this with the sighted cams. More compression breeds more quirks than power with street fuel. You have to remember that everybody's gas at their octane rate does not perform the same way. There is substantial performance variation between equally rated brands and geographical locations within brands.



-- Essentially the L31 from GM and its iron and aluminum copies without porting will deliver a solid 375-380 hp from 5800 to 6200 rpm, with torque around 390 to 395 pound feet 3600 to 4200 rpm. Examples would be the GM L31, the FloTek, the E-Street. With pro porting and tuning these can be pushed into the 410 hp range at 6000 to 6200. so we're not talking crazy things to get here.


-- More aggressive heads in iron like the EQ350 or aluminum like the lowly ProComp 3003, to the likes of Dart and World offerings will edge into the 420 range without much effort



-- The more aggressive chambered and bigger or better configured ported heads

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  #47 (permalink)  
Old 07-14-2019, 02:13 AM
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I had to break off in the middle of my typing to listen to wifey brief me on neighborhood divorces, like I care.


Back to heads if I can pick up my thoughts.





-- The more aggressive chambered and better configured port heads the better the power output. In a comparison of piston crown shape to head combustion chamber shape one thing that stands out is that a better configured chamber head over a round dish piston of the SBC 350, produces equal or better power than an L31 style head over a D dish piston. so what you can take away from this is combustion chamber shapes are very important.


Bogie
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  #48 (permalink)  
Old 07-14-2019, 01:09 PM
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Ok now I am stumped.

Pulled plugs and did compression test. All cyl right about 150 except the #2 which was about 135. 1/4 turn on the rockers and itís 150 with the rest. I am/was really concerned I have bent a valve or something. Anyone help he interpret this?

Also, to bogies point. Yeah, I hate the intake, but I hat a gay hole in my hood even more. Could/should I change the comp ratio with Different head gaskets?

Guess I should at least send this box to mad?

And Eric nova, please resend link itís a dead link.
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Old 07-14-2019, 01:15 PM
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https://www.high-performance-engines...ine-p/sp04.htm

Should be the short block I have...
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  #50 (permalink)  
Old 07-14-2019, 02:32 PM
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Quote:
Originally Posted by Onepieceatatime7 View Post
Ok now I am stumped.

Pulled plugs and did compression test. All cyl right about 150 except the #2 which was about 135. 1/4 turn on the rockers and itís 150 with the rest. I am/was really concerned I have bent a valve or something. Anyone help he interpret this?

Also, to bogies point. Yeah, I hate the intake, but I hat a gay hole in my hood even more. Could/should I change the comp ratio with Different head gaskets?

Guess I should at least send this box to mad?

And Eric nova, please resend link itís a dead link.
Compression test says bent valves are highly unlikely.

Any idea what the current head gaskets are??

The previous distributor link I posted still works for me, but here is another if you need it...or just search "SBC small cap HEI" on Ebay and look at the Self Contained or Ready-to-Run versions as those don't need an external box or computer to run them.
https://www.ebay.com/itm/Ready-To-Ru...d312fc4b7fbf00
https://www.ebay.com/itm/Fits-Chevy-...YAAOSwRrJdECo3
https://www.ebay.com/itm/Chevy-Big-S...gAAOSw7ThUnXek

I was looking in your photo album, is the engine in picture #3 the one we are working with here??
Is that an RX-7 engine swap deal?? I couldn't tell what the engine bay is.

If that pic is the engine, that air cleaner/carb hat could possibly be the problem...Holley carbs will act very screwy if anything is too close/low over the top of the bowl vents, it causes all kinds of metering problems..
How much space is there between the underside of that hat and the top of the bowl vents or choke tower??
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  #51 (permalink)  
Old 07-14-2019, 02:53 PM
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if the engine runs OK with no load, and poorly when under load, then fuel mixture is usually the problem. Ignition systems aren't that sensitive on a NA engine deal
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Old 07-14-2019, 03:41 PM
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Quote:
Originally Posted by Onepieceatatime7 View Post
Ok now I am stumped.

Pulled plugs and did compression test. All cyl right about 150 except the #2 which was about 135. 1/4 turn on the rockers and itís 150 with the rest. I am/was really concerned I have bent a valve or something. Anyone help he interpret this?

Also, to bogies point. Yeah, I hate the intake, but I hat a gay hole in my hood even more. Could/should I change the comp ratio with Different head gaskets?

Guess I should at least send this box to mad?

And Eric nova, please resend link itís a dead link.
I run this air cleaner on the current carb Edlebrock Thunder mounted on a GMPP, LT1/4 intake on Frankenmouse.

https://www.ebay.com/itm/Chrome-Supe...ry!98112!US!-1

I also run the same distributor as Ericnova llinks. I got mine from Jegs they sell it as part of their Speedmaster/Procomp line. Parts are unique to this in terms of cap, rotor, and module so it's a good idea to buy a set of spares as you probably can't find parts for this distributor at the corner parts store. I've been putting together a lower buck hot rod project for this fourm. Forst I wanted to get some time on parts leading to the completed project. So I removed the 454 TBI on the engine and its distributor replacing them with the Speedmaster distributor and rebuilding what looked like a decent Edlebrock Thunder from EBay at a very good price. My view is he tried to tune it but couldn't, but he tried plenty of evidence of that with not understanding what the problem was. What he missed was a float with fuel leaking into it. I replaced the floats, put in a kit, increased the lean jetting these come with by one step richer on jets only. The engine runs very strong but to get the kind of mileage that just happens with the TBI, if that's what I want, I have to work for it; one romp on the throttle puts a simile on my face with a dent in my wallet.

Of you use the Speedmaster on a flat tappet cam it's good to go. If you run it on a roller the simple way is just buy their bronze gear. This is because of two things you run into. First Speedmaster uses the GM size .491 inch shaft not the afyermarket .5 inch shaft. The other is they use a larger diameter retaining pin than GM which means if you use a GM gear that fits the shaft, you will need to drill out the pin's hole in the gear to the larger size used by Speedmaster's shaft. Their dog house module pins differently than GM, so unless you mount a GM style module on the firewall and jumper it to the distributor, you do need to have a just in case spare. This also uses the 92 mm Speedmaster cap there are seveal that look similar but don't fit, same goes for the rotor. This distributor is impedance matched to the Speedmaster/Procomp PCE 91 E core coil. Not matching module to coil impedance eats weaker which is usually the module, this is a generality of electronic circuits not exclusive to Procomp/Speedmaster.



I've got a few thousand miles on this stuff without issue.

Bogie
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  #53 (permalink)  
Old 07-14-2019, 05:46 PM
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I'd be leery of the rest of the valve adjustments if one was too tight. Evidently your method was off. Get it revved up and a couple more might not close all the way and next thing you know you have some burnt valves. I'd start over and do them all.
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  #54 (permalink)  
Old 07-15-2019, 07:44 AM
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Quote:
Originally Posted by EragonSuperH View Post
Think of electricity like fluid pressure. When you're pumping a fluid through an orifice and the pressure gets to be too great to force it through as fast as the pump wants to, where does it go? Same way with a turbocharger when you let off the throttle and you get that fluttering sound, that's air pressure building up and forcing its way back through the "pump" in this case the turbocharger. Its the same concept for electricity, just on a sub atomic scale

Sent from my VS996 using Tapatalk

I didn't see this until now. When comparing electricity to water, this web page does it much better. Water circuit analogy to electric circuit
A lot to learn there about voltage, current, resistance.
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  #55 (permalink)  
Old 07-15-2019, 07:53 AM
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Quote:
Originally Posted by 55 Tony View Post
I didn't see this until now. When comparing electricity to water, this web page does it much better. Water circuit analogy to electric circuit
A lot to learn there about voltage, current, resistance.
Thank you for finding that. It was essentially what I was trying to say, it just does a much better job of saying it

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  #56 (permalink)  
Old 07-15-2019, 07:58 AM
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Quote:
Originally Posted by EragonSuperH View Post
Think of electricity like fluid pressure. When you're pumping a fluid through an orifice and the pressure gets to be too great to force it through as fast as the pump wants to, where does it go? Same way with a turbocharger when you let off the throttle and you get that fluttering sound, that's air pressure building up and forcing its way back through the "pump" in this case the turbocharger. Its the same concept for electricity, just on a sub atomic scale

Sent from my VS996 using Tapatalk

I didn't see this until now. When comparing electricity to water, this web page does it much better. Water circuit analogy to electric circuit
A lot to learn there about voltage, current, resistance.
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  #57 (permalink)  
Old 07-15-2019, 07:59 AM
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Quote:
Originally Posted by ericnova72 View Post
Compression test says bent valves are highly unlikely.

Any idea what the current head gaskets are??

The previous distributor link I posted still works for me, but here is another if you need it...or just search "SBC small cap HEI" on Ebay and look at the Self Contained or Ready-to-Run versions as those don't need an external box or computer to run them.
https://www.ebay.com/itm/Ready-To-Ru...d312fc4b7fbf00
https://www.ebay.com/itm/Fits-Chevy-...YAAOSwRrJdECo3
https://www.ebay.com/itm/Chevy-Big-S...gAAOSw7ThUnXek

I was looking in your photo album, is the engine in picture #3 the one we are working with here??
Is that an RX-7 engine swap deal?? I couldn't tell what the engine bay is.

If that pic is the engine, that air cleaner/carb hat could possibly be the problem...Holley carbs will act very screwy if anything is too close/low over the top of the bowl vents, it causes all kinds of metering problems..
How much space is there between the underside of that hat and the top of the bowl vents or choke tower??
sorry for asking to post links again....my ipad was preventing new windows popping up. That is the engine in the picture and the air intake i am using. I don't think it's the air breather setup as it ran right before........and when I have taken it out the lat couple times there has been no breather on it.
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Old 07-15-2019, 08:00 AM
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Sorry, somehow I posted that twice? I thought I used to have a delete function?
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Last edited by 55 Tony; 07-15-2019 at 08:06 AM.
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Old 07-15-2019, 08:02 AM
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Originally Posted by EragonSuperH View Post
Thank you for finding that. It was essentially what I was trying to say, it just does a much better job of saying it

Sent from my VS996 using Tapatalk

Yes, it's similar to how they taught us in electronics school. There is a lot more if you scroll down, if you didn't already.
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  #60 (permalink)  
Old 07-15-2019, 08:38 AM
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Beginning to think my problem is in my wiring, as when it ran fine before was before I wrapped and bundled to make it look pretty, and the battery is on the passenger firewall now. So I have a chevy 1 wire alternator wire running across there as well as all the MSD and other stuff bundled into about a 1" group.

Perhaps the coil fix was a part of it, but this might be another big part as I have read that alternator is the worst for interferance. That, the plug wires in parallel on the 5 &7 and the dizzy and coil and alt wire in that bundle, even if they're not next to each other.

So I'll go through the valve adjustments looking for any gremlins and then tear apart my sweet wiring job. If I go with that other dizzy I'll need to pull all the MSD wiring out anyway. so I'll get it back to ugly and seperate and see what happens.

Edit: and also adjust the idle air/fuel mix
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