350 TBI tows 5000/6000lbs

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donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Fri Jun 08, 2018 10:10 am

n2xlr8n wrote:
Fri Jun 08, 2018 9:28 am
Truckedup wrote:
Fri Jun 08, 2018 6:54 am
donforeman wrote:
Thu Jun 07, 2018 9:42 pm


I like this site. Its an old sales info page for GM. I downloaded the copies for my vehicles. I have seen C2500 trucks with 454. There was an ad for one a few days ago I considered, but the owner started talking about a radiator problem and I did not want to drive that far to find trouble.
https://www.gmheritagecenter.com/gm-her ... -kits.html
Uhhh, I still think the 454 was not available in a 1/2 or 3/4 ton for 88-98 , just the one ton series like a dually...
Not a truck per se, but I owned a 88 (or 89) Suburban 3/4 ton 2WD with the 454/T400. I regret selling it.
http://www.roadkill.com/chevrolet-454-s ... rnout-fun/
Or the 454ss half ton, not great for towing or a hot rod, but it is a big block in a half ton.

gmc406
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Re: 350 TBI tows 5000/6000lbs

Post by gmc406 » Fri Jun 08, 2018 10:12 am

My uncle back in the day had a 93 3/4ton with a 454.

cardo0
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Re: 350 TBI tows 5000/6000lbs

Post by cardo0 » Sat Jun 09, 2018 11:38 am

If you're thinking engine swaps I meet a guy at a truck stop that put a Cummings 12V in his van. The 12V has mechanical fuel injection and alot less headaches to swap with. You can see alot of 12V donor trucks up in the rust belt states. My '96 dually has 280k mi and the oil level doesn't change between change intervals. I'd swap in a Cummings before any BB if the money was the same.

donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Sat Jun 09, 2018 6:36 pm

I am not really looking to swap anything. I think if a tune, cam, bowl port and springs will not do it, I should look at big blocks trucks or vans with hd running gear. The 4l60e and 14 bolt sf rear will only hold so much. I did look at the cummins swap into a chevy van on YouTube. Its a total hack job on the g van. They have to cut way back into the van for added length and a custom dog house. I drove the van today to pick up a Kalamazoo 7A band saw. Its a super nice driving van, just under powered at times.

donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Sat Jun 16, 2018 8:57 am

I got a cheap Jet Stage 1 tbi chip to look at second hand. Its for a 1995 350 4l60e C/K truck so I put it in the van as a test as the specs were close enough not to blow anything up.

Main Spark vs Map Table was bumped by 1.1-3.2 degrees in a few cells. This is supposed to be for a stock truck tbi engine, but a lot of the timing changes were at 5000-6000 and WOT so not even noticeable as the engine never runs that high.
They bumped the fuel cut off from 98 to 115 mph, the only way my van will ever see that, is if it falls off a cliff.
The main fuel table was increased in almost the same areas they bumped the timing. Probably to combat detonation by making the engine very rich.

My self burned chip with only revised shift points in a few gears was much more noticeable when towing. I cant believe, companies get away with selling this for $150 and up. My sample cost almost nothing though, so it was almost worth it just for the education on what not to do.

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Re: 350 TBI tows 5000/6000lbs

Post by cardo0 » Sat Jun 16, 2018 1:55 pm

donforeman wrote:
Thu Jun 07, 2018 1:44 am
I never tow in OD with the 4l60e. Like I wrote before 3rd and 2nd are the gears I use when towing. I did purchase a take out 14097395 roller cam (196/206@109) from a marine engine for the van in case the block happens to be roller comparable. If its not then, I will figure something else out and I can get rid of the roller cam easy for what I gave for it.
Okay that's the cam I have in my '94 Z28 now. Didn't want to change the valve springs and I liked what that cam does for the RamJet 350 motor - something like 400 ft-lbs and a flat curve. So in my Z28 that cam burns rubber like more than I can handle for a decent launch for the 1/4 mi. Had to change back to stock stall converter from the 2200 - 2400 TC I was using trying to reduce the wheel spin. That tight LSA makes some great torque down low.

Installing that cam and fix/upgrade your tune sounds like you have a good plan there. And if you pop the heads use a 0.015" Felpro shim gasket should give you some quench - if the pistons and compression compliment it. I don't think you need a whole lot more flow for what you are trying to do. I think you mentioned swirl port heads and I recall those ports are fairly big to start with.

Yeah, it reads like you are doing the best you can for the money with that cam and trying it will tell you what more you need. Good luck.

donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Sat Jun 16, 2018 4:45 pm

Thank you for the advice. Yes, I have not heard anyone complain about the ramjet cam for low rpm use, so I decided to grab one when I found it reasonable. I did get a few victor shim gaskets on close out a few months ago, along with a 180 degree t-stat and other engine gaskets. All of it is on the shelf, waiting for the slow season so I can tear it all apart for a weekend.

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Re: 350 TBI tows 5000/6000lbs

Post by Truckedup » Sat Jun 16, 2018 4:54 pm

Around 1978-80 construction was slow so i took a job at a fleet garage for a time..I was not a real skilled engine mechanic so I did a lot of suspension work and some things no one really liked to do.....And there was a rash of bad cams in 350 Chevy engines during that time.. Hated to change cams in those damn vans...Or pull the heads..... :D
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire

va454ss
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Re: 350 TBI tows 5000/6000lbs

Post by va454ss » Sat Jun 16, 2018 7:55 pm

TriY headers, h pipe, free flow muffler, electric fans, and underdrive pulleys.

donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Fri Oct 26, 2018 9:16 am

The van made it through the summer towing local just fine. I pulled the van apart yesterday and it is a full roller block, tapped holes and all. So I will try the 196/204 109Lc 3 deg adv ramjet cam I have. I want to keep the factory exhaust manifolds for heat and noise, they are inches from the driver and passengers feet, besides a "good" header is not available. The exhaust is getting replaced with 409 mandrel bends, dual 2" to single 3" and a good muffler. I did look at the ramhorn style manifolds, but the center dump looks to run right into the knock sensor on the factory block. With the cruddy fuel we get at times, I really want to keep the knock sensor functioning as intended.

So a few more questions...

Steel shim gaskets were recommended to bump the compression slightly from the 9.5 factory spec. The block is not coming out for resurfacing. I saw here where some here say only use the thinner gaskets with fresh surfaces? I can go either way with this to be safe.

The engine has the 193 swirl port heads that I am considering cleaning up the valve bowls on. The engine has 109k on it and the intake valves look fairly clean, but I can't see pulling the heads not having a mag /valve job done along with new stock vortec roller valve springs. I have not priced machine work lately but I am thinking that will be around $300+ especially if I have them surfaced . Are the heads worth putting that amount into, when new vortecs from Summit are 800? One step up from that is summits aluminum 170cc angle plug heads for TBI, but with my low rpm goals, and stock manifolds for exhaust, I am not sure if I would be using any of the benefit the heads provide. I lucked out and was able to pick up an edelbrock tbi manifold and vortec tbi manifold for almost nothing local just because most people don't want to mess with tbi at all anymore. So I have the intake manifolds for either head style.

I have tried to do some research on the swirl port heads and some say they lost torque up to about 3500 and some mileage when swapping to the newer vortec heads. I really only care about improving the engine in the 2000 to 4400 range. I am not sure the engine would be up to pulling grades reliably for long time periods at 5500 rpms so I have the fuel cut at 4900 and WOT shift points at 4500. I know this is speedtalk not towtalk, but really the knowledge here seems to be a step above the lottery of answers you get other places, so I keep coming back to read and research. Thank you for all the help so far!

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Re: 350 TBI tows 5000/6000lbs

Post by Carnut1 » Fri Oct 26, 2018 10:32 am

TBI gets a bad rap but they are a nice motor for what you are doing. What I would do if it was mine is get the 193's magged, if they are crack free I would have the guides and a good three angle valve job done with a light surface mill. New seals and the roller springs, I would port the bowls and round the pinch bulges. The exhaust manifolds are pretty bad but some porting on them helps. The stock intake for a mild build I used to radius the tbi barrels which is tough on the lower H. I have not worked on the Edelbrock but it may be a similar design. The tbi itself likes to have the top of the casting milled down and a wide radius ground into it, tbi's pull air from the sides so this mod helps, extra injector gaskets can raise the injector pod also. With that cam I would run a 1.6 rocker on the intakes and would use the thin steel head gasket. I have build a bunch of these and even with stock valve sizes just what I wrote picks them up quite a bit with no down side. Thanks, Charlie
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donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Fri Oct 26, 2018 11:34 am

Thank you for the response. Crack checked heads and shim gaskets it is. According to other forums, the Edelbrock tbi manifold is only worth about 4hp over the OEM tbi manifold on a stock engine. I may still use it, but definitely would not pay new price for it. The stock intake has a port connecting the two barrels together while the edelbrock keeps them separate. If I use the edelbrock I will put that passage back in.

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Re: 350 TBI tows 5000/6000lbs

Post by Carnut1 » Fri Oct 26, 2018 12:44 pm

donforeman wrote:
Fri Oct 26, 2018 11:34 am
Thank you for the response. Crack checked heads and shim gaskets it is. According to other forums, the Edelbrock tbi manifold is only worth about 4hp over the OEM tbi manifold on a stock engine. I may still use it, but definitely would not pay new price for it. The stock intake has a port connecting the two barrels together while the edelbrock keeps them separate. If I use the edelbrock I will put that passage back in.
So you will cut a section out of the divider between the tbi barrels in the Eddy intake? I do not think I would do that on a tow motor. I know I have cut a deep notch on stock manifold to share air from small stock throttle body but that mod required welding. I would just give the Eddy a quick once over for flow improvements and bolt it on. Thanks, Charlie
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Fri Oct 26, 2018 1:00 pm

Yes the factory 305 tbi engines have a more traditional slot from the factory, its small but there right on top. The 350 tbi intake have a smaller port about 1" off the upper floor. I was guessing that the factory must do that for a reason on both engines and the Edelbrock not having it was due to production costs. I just thought that may be one reason the edelbrock with its larger passages doesn't do a lot better that the factory intake. It's not something I know for sure would help and its a pain to pull the manifold in the van so I will leave it alone or just use the factory manifold with the port cast in.

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Re: 350 TBI tows 5000/6000lbs

Post by Carnut1 » Fri Oct 26, 2018 1:14 pm

eq vortec 5.jpg
Someone will state that l31 vortecs are way better head. In some respects they are, keep in mind if you were to use stock or as I pictured here a set of EQ vortecs the timing curve will need adjustment and may not produce more torque in your towing rpm. I am a fan of these EQ's I ported up one intake, exhaust and a chamber at DV's shop for a iop demo. I don't know the retail price on these but it is a nice heavy duty head and it may only be a few $ more than reworking the swirl ports. Just making trouble for you. Thanks, Charlie
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