350 TBI tows 5000/6000lbs

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donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Tue Nov 13, 2018 7:09 pm

Part 14097395 sometimes called the ramjet cam. 196/204 109Lc, 3 degrees advanced. I think it will do fine for what I am doing.

Newold1
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Re: 350 TBI tows 5000/6000lbs

Post by Newold1 » Tue Nov 13, 2018 7:29 pm

That cam works pretty well in a 350 mild build. I myself like the 12551705 LTI cam as its 201/208 with about .450 lift but the 117LSA works better with the TBI ECM and requires in some cases no re-tuning depending on total changes. If you use the the RamJet cam with its 109 LSA you will have to most likely do some retune to get it right. I believe your stock cam was about 191/195 at about .420 lift with a 115LSA for the TBI's.
The Older I Get, The Dumber I Get :wink:

donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Tue Nov 13, 2018 7:51 pm

Thank you for the feedback. I don't mind burning chips. It's not a factory one in there now. I was able to improve the towing by revising the shift points even with the factory engine.

Newold1
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Re: 350 TBI tows 5000/6000lbs

Post by Newold1 » Tue Nov 13, 2018 7:56 pm

Don:

Looks like you got the bases covered pretty well. Let us all know how it ends up running and towing when you get it dialed in.

Regards,
Newold1
The Older I Get, The Dumber I Get :wink:

pdq67
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Re: 350 TBI tows 5000/6000lbs

Post by pdq67 » Tue Nov 13, 2018 9:19 pm

IMHO, Chevy's old -929 cam is hard to beat!

And I think Crane might make one with tighter LCA's and stuff for the STOCK class roundy-round guys.

pdq67

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Re: 350 TBI tows 5000/6000lbs

Post by cardo0 » Tue Nov 13, 2018 9:56 pm

That RamJet cam in my LT1 does have idle fluxuating issues and rarely smooth at 850rpm. Likes to climb to 1000rpm or more. PCM is not dealing with the added overlap. Seems very temperature sensitive when starting. But above 2500rpm everything is good. Lots of torque and good throttle response. WOT will burn rubber and put you sideways. Done breathing by 5500rpm but will slowly wind higher.

So what I'm saying is the motor should run as is but will be seem stupid when starting and idle'n.

Sorry to read your head problems. I think now your heads are off your committed to some good heads. I really like my World Products Torquer II on my C3 corvette. But when I bought them the vendor pocket ported for only 100 bucks more. Nowdays I've met enough good performance build shops locally that I would buy heads through them as they will warranty their own work and have a face to talk to instead of a PC monitor.

Great thread here an thanks for posting.

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Re: 350 TBI tows 5000/6000lbs

Post by Roadknee » Wed Nov 14, 2018 12:06 am

That cam will work great for what Don needs it for. I've tuned that same ECM on 350s with much larger cams and they idle just fine.

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Re: 350 TBI tows 5000/6000lbs

Post by econo racer » Wed Nov 14, 2018 2:57 pm

I always wanted to try the comp cam adv. 252 - 425 lift. Old high energy cam. I will have to agree you need good low rpm torque. Oh the cam is 206 deg at 50. I would like to try this cam in a 400 sbc and try to see what the most mpg I could get in a s10.

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Re: 350 TBI tows 5000/6000lbs

Post by gmc406 » Wed Nov 14, 2018 6:12 pm

econo racer wrote:
Wed Nov 14, 2018 2:57 pm
I always wanted to try the comp cam adv. 252 - 425 lift. Old high energy cam. I will have to agree you need good low rpm torque. Oh the cam is 206 deg at 50. I would like to try this cam in a 400 sbc and try to see what the most mpg I could get in a s10.
Had that cam in my 350 and my 406. Lots of idle twist. Run outta breath in both engines by 5000, but I never expected more.


An additional note, that cam in my TBI 406 in my 91gmc would run 13.60’s shifting at 5000. The truck sounded absolutely bone stock. At that time it was what I wanted

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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Sun Nov 18, 2018 12:00 pm

I spoke to Jegs a few days ago, I was told they have no way to actually take a head apart to see what they are selling. I did find out jegs vortec heads were supplied by another vendor and recently Jegs started slipping in standard rebuilder grade vortec heads made by promax in as the same part number 514080 without changing the description. Not made in the USA, no bronze liners, no hd retainers or springs. The spring to seal clearance problem was their combo of retainers and locks. Upgrading to slightly stiffer spring and retainer set from Summit will fix the problem. I have them here. I have to order a cutter to trim the inner spring seat slightly as the import heads are larger in this area than factory vortecs. They also have a odd size seal. 0.550

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Re: 350 TBI tows 5000/6000lbs

Post by levisnteeshirt » Sat Dec 08, 2018 9:14 am

gmc406 wrote:
Sat Nov 10, 2018 11:23 am
levisnteeshirt wrote:
Thu Nov 08, 2018 5:26 pm
i have a 95 k1500 350 5 speed ,,, set the valve lash ,, factory is way tight , i gave em 1/8 turn past zero hot idling , i could feel a difference ,, some had over a full turn of preload ,, the spacer that sits under the factory air cleaner has to go ,,, its function has to be to limit power ,, could do away with the tube going to it and put a breather on that tube from the valve cover ,,, placing the air filter straight on the TBI i also felt a difference , no doubt ,, i gave it about 5 degrees more initial timing ,,, I recently put mid length headers on it with the Y pipe for the headers and gutted the converter ,,, i also put the 1in open spacer on it ,, the spacer seemed to do more than the headers ,,, i put one of the 18 psi springs in the TBI ,, huge difference but i could watch the gas gauge fall so i took it out ,,, i think my engine is a little tired since the headers and cat gutted didnt seem to do much ,, but i had on it before 2 resonators from summit after the cat ,, it sounds good and not loud even after gutting the cat ,,, i have a pair of HO 305 heads I'm gonna try on it ,, might do an in frame rebuild if i pull the heads and the holes all look good
You are in desperate need of a custom tune. Then everything would come together. The stock computer can only learn so much until it needs a tune. Especially when you change the springs in the TB. It was running to rich.

P.S, I don’t think there was any need to swap springs in the first place. Before I went to my 406, I had my 350 with Eddy heads, mild Comp cam, headers, etc.... I was still running stock TB, with stock injectors, stock fuel pump and stock fuel press. All I had was a custom tune to pull it all together.
It's running quite well , mpg seems to be better with the tbi open spacer after the headers were added , I put on a set of 31 10.5 15 tires and it's mpg is up even after that. I'm almost afraid to do anything else to it , I might put a good coil and MSD on it , looking at an electric cut out fan to see if I can adapt one to a tbi motor ,, the later model 5.7 used a threaded hub water pump , if it's the same thread I may try one,, not a fan of all electric units. An underdrive pulley may be beneficial too. I have to wonder if the L98 cam would be good for towing

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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Sat Feb 09, 2019 4:04 pm

After a few weeks of frustration, I got the van back together. I put it on the chassis dyno just to see, the fuel and timing tables are still in progress. The cam and head swap flattened out the torque curve. Nothing else was changed that would really change the hp, the GMPP TBI intake and SS exhaust from the factory manifolds were just replacements to get the job done. I did upgrade the valve springs slightly. I removed the shim gaskets I was originally planing on using, after fighting with the Jegs heads. I put the .026 composites in their place as I just did not want any leak problems and I needed the van to be reliable. The results so far do make a noticeable difference in towing, but I was hoping for more, ha ha. It looks like I didn't move the rpm range of the engine at all, so that's a positive. I did gain some noticeable power on the butt dyno (not tested on the chassis dyno) switching the chip to a factory 1995 caddy lt timing table from a vortec truck table, but the knock counts started piling up as soon as I hooked the enclosed trailer to the van and pushed it hard. I took it back out for safety. I will work on it some more later. The cam was super easy to dial in. I think the 1994-95 computer may be more forgiving that the early versions.

Here is a picture of the before and after. Yes the fuel mixture was a little lean at WOT, that was fixed later and not tested yet. On the last test I locked the trans in 3rd and locked the converter clutch. This is not the way it would drive, just wanted to use the dyno to load the engine down low to get an idea if I lost anything down low. So far the reaction on the other message board is the engine is still missing some power, but I am not that unhappy with a 40hp / 50ft lb gain so far, with the vortec head and small roller cam swap. Of course I always wish for more. Comparison power is Dyno Dynamics Dynojet guess. They do not calibrate that number nor claim it to be accurate. I set the roller lifter preload the standard way 1/2 turn after zero lash, but another person instructed me to set it running and only 1/4 turn or I would be loosing HP? I have not pulled the covers yet as its a huge pain on the van and I have not had any trouble in the past.

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Re: 350 TBI tows 5000/6000lbs

Post by prairiehotrodder » Sat Feb 09, 2019 4:21 pm

Sorry i never read your entire thread but i just thought i'd post some experience i recently had with a stock 350 TBI engine. I've always thought they were pretty gutless but i had one from a 94 chevy pickup with 300,000 kms that i tossed into a 80 malibu 4 door. I notched out the center intake bolts on a stock iron Q-jet intake and tossed on a stock wore out Q-jet carb and this thing is a beast ! The thing destroys tires and goes like crazy. Only mods to the entire wore out junk engine was the stock 4 barrel carb and intake, plus a set of cheap headers to fit the car. Thats it. I'm now a believer that they can actually make some power once you ditch the TBI.

Kudo's to anyone who can keep the TBI and still tweek and tune some power.

Brian
The Word of God is quick and powerfull
www.therocketshop.blogspot.com

donforeman
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Re: 350 TBI tows 5000/6000lbs

Post by donforeman » Sat Feb 09, 2019 5:42 pm

Thanks for the feedback. More than a few people have mentioned switching to a carb. Really though the logging software registers 95kpa at WOT all the time, so the tbi is not as big a restriction as some suggest for truck use and under 4500 rpm. Unless I am missing something?? We are about 1300 feet above sea level. I think when I checked it was about 97 Kpa for that altitude. When you start hacking the factory computer there is a lot of pitfalls. One is the software to do the changes is best guess. The GM code and definitions were never released to the public. All the advancements are sort of reverse engineered. The second thing I have found was a lot of miss information posted online about how and what to change to get results. Its almost easier to mess things up than to improve as the definitions are not well explained. A lot of chip bin files I downloaded as samples have huge mistakes in them and people are driving around that way thinking its great. My own chips included, I really messed up the timing tables by zeroing out a bias flag because that was suggested on another forum, then sort of I find out how it works and have to undo. Its fun learning new things though. This ten year old photocopy has been the most reasonable source of info I have found. http://www.gmcmi.com/wp-content/uploads ... System.pdf

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Re: 350 TBI tows 5000/6000lbs

Post by travis » Sat Feb 09, 2019 6:15 pm

Maybe I missed it, but what are you using for exhaust?

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