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350 TBI to 383 with Flo Pro Swap

Maybe I already posted this in your thread, but I used the switch when I had a 700r4. I tried the vacuum switch, but I didn't feel like it operated correctly. It's a little bit of a pain having to remember to use. Mostly I would forget to turn it off and when coming to a stop the drivetrain would start bucking. There's those couple of seconds when you like what the...? then remember to disengage the TCC.

I can also say, if you have an engine with enough grunt, it's nice to be able to lockup the TCC when it normally wouldn't. One place I used it a lot was pulling the high mountain passes in 2nd and 3rd. Usually I could hold a steady speed in 2nd or 3rd and locking up the TCC kept the trans at normal operating temperature.

As far as the IAC and engine dying, I'm only having trouble when the engine is cold first thing in the morning or after it's been parked all day at work. What I did was set the IAC at 5-6% IN GEAR not park. One of the PF4 techs, Nate S, had posted on the PF4 forum that it could be done either in park or gear. Now it operates like I expect an EFI automatic vehicle to. In park it idles at about 750 RPM with IAC at 0%, then in drive it drops to 575RPM with IAC at 5-6%.

My starting point was where the idle speed screw needs to be for the engine to idle at 750 RPM in Park with IAC at 5-6%. I put the trans in Drive and then dropped the target idle until IAC was at 5-6%. That's been working good, as I said the only time I have an issue is cold engine put into gear the first time. If I 2 foot it for the first shift, then it's fine.
 
Use the automatic 4th electric lock up from BowTie overdrive's. If you want manual lick up in 3rd and second you can do that also
 
mrk5 said:
Maybe I already posted this in your thread, but I used the switch when I had a 700r4. I tried the vacuum switch, but I didn't feel like it operated correctly. It's a little bit of a pain having to remember to use. Mostly I would forget to turn it off and when coming to a stop the drivetrain would start bucking. There's those couple of seconds when you like what the...? then remember to disengage the TCC.

I can also say, if you have an engine with enough grunt, it's nice to be able to lockup the TCC when it normally wouldn't. One place I used it a lot was pulling the high mountain passes in 2nd and 3rd. Usually I could hold a steady speed in 2nd or 3rd and locking up the TCC kept the trans at normal operating temperature.

As far as the IAC and engine dying, I'm only having trouble when the engine is cold first thing in the morning or after it's been parked all day at work. What I did was set the IAC at 5-6% IN GEAR not park. One of the PF4 techs, Nate S, had posted on the PF4 forum that it could be done either in park or gear. Now it operates like I expect an EFI automatic vehicle to. In park it idles at about 750 RPM with IAC at 0%, then in drive it drops to 575RPM with IAC at 5-6%.

My starting point was where the idle speed screw needs to be for the engine to idle at 750 RPM in Park with IAC at 5-6%. I put the trans in Drive and then dropped the target idle until IAC was at 5-6%. That's been working good, as I said the only time I have an issue is cold engine put into gear the first time. If I 2 foot it for the first shift, then it's fine.
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I think you did mention trying the vaccum switch and not liking it. I may just try the simple switch and see how I get along with it first.

I appreciate the information about your idle/IAC settings. I'll see how it does with the lower settings in park, if that doesn't do the trick I'll give your method a try.
 
It has been awhile since I provided an update. The el cheapo 02 sensor was working fine, and I felt like the unit was dialing in except for putting into gear before the coolant temp reached 165F. I was working on getting that dialed in with help from the Pro Flo 4 thread.

Now what I screwed up. I decided to go ahead and run the new engine with the old radiator, heater core, and heater core hoses knowing that they really needed to be replaced. They all had minor leaks that I had been living with for over a year before the old motor died.

Sometime toward the end of January I started to notice white smoke/condensation in the exhaust. More than was usual I thought. After the engine warmed it went away and everything was running fine. Until one morning when temps had dropped considerably the white in the exhaust never went away and actually seemed to get worse. So I figured I must've blown a head gasket (or possibly worse, cracked a head). So I ordered up a radiator with dual electric fans, a new heater core, and all the hoses.

As I waited for temps to warm up enough to work on replacing these parts I started to ponder what might've caused the possible issues at hand. It was recommended I do a compression test, so I added that to the to do list. My pondering brought to mind to instances that finally dawned on me probably were the culprit. On two separate occasions I was cruising along and all the sudden my factory coolant temp gauge (sensor in the head) started to climb, got all the way to 230ish while the Flo Pro sensor read normal (in the intake manifold), then the thermostat must have opened and temps dropped back to normal. All this occurred over a span of probably 10-20 seconds. I figure those little leaks grew into bigger leaks and must've allowed for air pockets to form in the system.

Now with the white in the exhaust I feel those little overheat episodes probably cracked a head (or two). I installed the radiator, heater core, and hoses last week and started it up, in no time at all I had white in the exhaust and a small amount of steam coming from the valve cover breathers. So I shut her down and disconnected the battery and plan to pull the heads this weekend.


Since I have limited to work on this project, with family and other priorities/projects requiring attention on my days off, I went ahead and ordered a set of heads today. I figure if the heads are cracked I don't have to wait on ordering heads and another weekend that isn't already filled up a month down the road. If I get lucky and its just a head gasket then I can decide if I upgrade or send them back.

https://www.summitracing.com/parts/mll-h8002k

I also got some head gaskets, intake gaskets, and sparkplugs. Now provided I didn't screw anything else up inside the engine I'm thinking this might be the prime time to go ahead and upgrade my camshaft.

So for all those more experienced folks out there, let me know what you think a good camshaft would be to fit the use as a daily driver, trail rig, and occasional tow vehicle for 4wheelers that would give me a nice wide flat torque curve. You can also tell me if I just screwed up buying those heads over just getting a new set of vortec heads.

I figure I'll probably go ahead and start another thread out there specifically for camshaft recommendations, but from what I have been reading something with these kind of specs might be close to what I'm looking for:
https://www.summitracing.com/parts/sum-8801/make/chevrolet
 
FWIW, my engine has always done the heat cycle thing you are talking about. It only happens the first time the thermostat opens. The PF4 CTS will get as high as 205 and the factory gauge in the head will encroach on the red zone. After the first time the thermostat opens, it never climbs like that again. It's more pronounced if I'm in stop and go traffic versus straight highway driving.

It's done this to me before and after the PF4 and with 3 or 4 different thermostats; a couple were 195, others 180, and the current one has 3 bypass holes. Also had 3 different radiators including the factory rad that was in the truck when I got it. The PF4 has just given me the CTS temperature to compare to the factory gauge. I also installed a new sending unit in the middle of the process.
 
mrk5 said:
FWIW, my engine has always done the heat cycle thing you are talking about. It only happens the first time the thermostat opens. The PF4 CTS will get as high as 205 and the factory gauge in the head will encroach on the red zone. After the first time the thermostat opens, it never climbs like that again. It's more pronounced if I'm in stop and go traffic versus straight highway driving.

It's done this to me before and after the PF4 and with 3 or 4 different thermostats; a couple were 195, others 180, and the current one has 3 bypass holes. Also had 3 different radiators including the factory rad that was in the truck when I got it. The PF4 has just given me the CTS temperature to compare to the factory gauge. I also installed a new sending unit in the middle of the process.
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Well that is interesting . . . . thanks for sharing.

Now I'm really curious what I'm going to find when I pull the heads off!
 
I don't think I would trust those "overseas" heads. They aren't much cheaper than US made heads really, you could get a set of Brodix, Edelbrock, or RHS heads for maybe ~15% more that would have quality castings.

On the cam you aren't far off for your application, I could look into some cams for you if you want, the comp cams aren't going to be $250 though, I can check Howards if you like, I think I could sell those for about $290 for a hydraulic roller cam only for a SBC newer roller block, depends on the cam. Howards is good stuff too.
 
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folkenheath said:
I don't think I would trust those "overseas" heads. They aren't much cheaper than US made heads really, you could get a set of Brodix, Edelbrock, or RHS heads for maybe ~15% more that would have quality castings.

On the cam you aren't far off for your application, I could look into some cams for you if you want, the comp cams aren't going to be $250 though, I can check Howards if you like, I think I could sell those for about $290 for a hydraulic roller cam only for a SBC newer roller block, depends on the cam. Howards is good stuff too.
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I definitely appreciate getting US made parts, but I'm also pretty budget limited after blowing my wad on the engine and PF4. I am also limited to getting Vortec style bolt pattern heads since I already have the vortec bolt pattern PF4.

- Edelbrock has the E-tec heads, but they are ~$1,500/pair.

- AFR has vortec heads at ~$1,700-$1,900/pair. They also have an off-shore casting "Enforcer 195cc" heads that are very budget friendly and have a vortec intake bolt pattern. But I would have to switch my valve covers and wait a bit longer to get them.

- Brodix & RHS: I didn't see any heads with vortec pattern, but may have overlooked something

- There are a handful of other offshore castings in both iron and aluminum: Promaxx, Summit, Jegs, Speedmaster, Engine Quest, etc.
 
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I apologize, I forgot about your Vortec Intake, you are correct, that does limit options more.

I completely understand the budget, just trying to make sure you don't spend money to have more problems down the road.
 
I'd also check your deck surfaces with a straight edge and feeler gauge. I'd be pretty mad if I had a brand new engine that was leaking coolant into the cylinders from only 230 degrees, that is a little hot but shouldn't cause major issues.

Before you pull the heads I would pressurize the cylinders and see if you can hear bubbling in the radiator.
 
@folkenheath if you have a good suggestion for a good set of budget heads for under or around $1,000 I'm open to suggestions.

Forgive my newbie ignorance, but what would bubbles in the radiator tell me other than I have either a blown head gasket or cracked head?

What is an acceptable level of deviation from perfectly flat deck?
 
It would only narrow down the cylinder to check is all. It may be obvious once you see the parts, but if it isn't obvious it may tell you where to look. Make sure hte valves are closed, or if you are pulling the heads just pressurize them all after you remove the rockers, it will be faster then.

230 degrees should not be blowing a gasket or cracking a head. Some racing engines running at 250 or more the whole time. Granted they would need higher pressure or different coolant that doesn't boil over, but my point is 230 degrees should not have done that.

As for the block and head deck, I would use a .0015 or .002 feeler gauge, if that fits I would get it redecked. The book says .003 in a 6" span, or .006 over the whole head. I don't trust that much warpage.
 
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I sent you a PM. I hope you get back in action without more troubles.

BTW, have you checked to see if that engine is still on warranty?
 
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I pulled the heads last Friday and found out what my issue was. When I pulled the no. 6 spark plug coolant came out, so that was the first indicator of what was to come.
When I was removing head bolts I found that one of the head bolts next to the no. 6 cylinder was completely loose and had backed out some.

20210319_164618.jpg

Sure enough, the head gasket was blown right there . . . .
20210319_165842.jpg

Moving on to the driver's side head; all head bolts were at least tight to the head, but there were a few I don't think would have hit that 65lb.ft. mark.
When I got the head out to inspect I found cracks between cylinders 3 and 5.

20210319_174802.jpg

So now I at least know what the problem was. I called S&J because this engine still should be under warranty, but they do state, "Professional Installation recommended."
I had to leave a message, so I'll try again tomorrow.
In the meantime @folkenheath got me setup with a camshaft that should wake this puppy up. And the heads, gaskets, etc. I ordered from Summit should be arriving today.

I'll look over those Blueprint heads to see if they look like they are worth a damn. And then I need to decide if I'll be installing them or something else.

More to come, but hopefully I'll have her up and running again in short order!
 
Bummer on the damage. That gasket doesn't look sealed very well between 4 and 6 either, how does the head and block look there? I would check the block for flatness there, everywhere, but especially there.
 
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I agree, checking the deck is next on my list.
I got everything pulled apart right before having to head to another commitment.

I did notice quite a few bolts that definitely didn't feel like 65lb.ft. I should've used the torque wrench to break them loose just to verify.
 
Usually the static friction is more than the kinetic friction during torqueing, so it should take more than 65 lb-ft to break lose a bolt that was torqued at 65 lb-ft.

Did they have any retorque clause in their warranty? Obviously they missed some because I have never had them move a lot, only barely or zero during a retorque, and most modern gaskets don't require a retorque. That bolt that backed all the way out was likely missed. Which also makes me wonder, if you are supposed to torque them in 3 steps, they missed it every time? Or they are just torqueing in 1 step?

Although if a bolt isn't torqued properly and there is not enough stretch to keep it under tension, it could work itself lose.
 
folkenheath said:
Usually the static friction is more than the kinetic friction during torqueing, so it should take more than 65 lb-ft to break lose a bolt that was torqued at 65 lb-ft.

Did they have any retorque clause in their warranty? Obviously they missed some because I have never had them move a lot, only barely or zero during a retorque, and most modern gaskets don't require a retorque. That bolt that backed all the way out was likely missed. Which also makes me wonder, if you are supposed to torque them in 3 steps, they missed it every time? Or they are just torqueing in 1 step?

Although if a bolt isn't torqued properly and there is not enough stretch to keep it under tension, it could work itself lose.
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Yeah that happened to me on my 6.2 diesel. We torqued in 3 steps but we must have missed a few in the 3rd round, a retorque solved the problem.
 
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