Thinking more about vortec heads, intake and cam for TBI - need input

[Mattchu60]

After towing around a enclosed trailer over the weekend to help my brother move with my 87' V10, its pretty clear that its not up to the challenge. Most of my time was spent either crusing at 35-45 mph when loaded or 55mph with my foot into it and most of the time spent in 2nd gear with the occasional drop into D (forget OD). Its just down on power, I can't imagine it was this bad from the factory. Going to get this this refreshed and powered up over the winter when its not needed much.

Here is the plan, I am not looking for massive power, primary purpose of this truck is for hauling and pulling trailers and wagons (its a farm truck).

Here is my plan:

- reman TBI short block (350ci)
- vortec heads, maybe new or rebuilt
- a vortec/carb intake (much cheaper than the GMPP intake for TBI) with a TBI adapter plate
- new cam - either the basic Comp Cams one http://www.jegs.com/i/Chevrolet+Performance/809/14097395/10002/-1
or the HT383E (any input from someone using these would be great)
http://www.jegs.com/i/Chevrolet+Performance/809/14097395/10002/-1
-Going to delete the EGR and the A.I.R. system, I'm in IA and dont have to pass emissions. Just trying to clean up the engine bay a little, also plan to install headers, so AIR would be hard to deal with.
- Headers to dual exhaust.


Also I have a Holley TBI 670cfm now. Picked it up used, but I read that they can be a pain to tune properly, so may just look for a 454 TB and put my 350 pod on it, I would update with one of the adjustable fuel regulators and a pressure gauge.

By far the biggest concern I have is the ECM and tuning. I have never done that, no clue how to do it, and afraid I would get it so messed up that I would ruin the motor.

I need some input from anyone with knowlege or has done something like this before. If you see something above that is way off or should be different, please comment. Would a L31 reman be a better choice since you get roller cam and vortec heads with it?

 

[Jims86]

For what you outlined, the current TBI heads are perfect. The biggest problem, from what I can see in your pics, is that you have 33"(?) tires, on a vehicle geared to use tires that were around 29"....like pedalling a bike up hill in high gear.
1st thing I woul do, befor spending money under the hood is address the final drive issue, with either LT235/75/15 tires, or change the gears in both axles to at least 4.10
this would, without a doubt, be the biggest return on $$$ spent.
Then see how she does when towing. I garentee you will see a difference.
only after that, if you want more power, dig into the engine.

Personally, I would choose the stock size tires, because the original braking power will also return, which is a far cry from what you currently have with the bigger tires.

 

[austinado16]

Good tip on the tire size and gear ratio. I've left mine stock with the 15's, and 3.42's, and it tows nicely.

 

[Mattchu60]

I think you guys are right on with the gear ratios as well. The motor is not in its powerband, but honestly its not running right (has a miss in the motor, we think its a burned valve) so I figure a rebuild is in order anyways. Plus its always fun to rebuild or improve the motor.

Im keeping an eye out for a 14 bolt, if I change ratios I may as well beef it up. I need new tires anyways, but dont want to buy new ones if I will be trading in for 8 lug wheels soon.

 

[Jims86]

I think you guys are right on with the gear ratios as well. The motor is not in its powerband, but honestly its not running right (has a miss in the motor, we think its a burned valve) so I figure a rebuild is in order anyways. Plus its always fun to rebuild or improve the motor.

Im keeping an eye out for a 14 bolt, if I change ratios I may as well beef it up. I need new tires anyways, but dont want to buy new ones if I will be trading in for 8 lug wheels soon.

I have driven low mile tbi squares, like only 2k on the clock, and they are pretty impressive, pop the pedal, and the whole truk twists a little.
For TBI, I would use a Melling MTC 1 camshaft, Full head rebuild, gasket match intake and exhaust ports, Edelbrock TBI performer, and a big body 5x11 Magnaflow muffler, single 2.5 or 3" exhaust.
no need for headers...stock manifolds better for reliability.
The beefier rear is a good idea if you work it that often, all you need to do is change your current fron to 8 lug.....1/2 and 3/4 used the same front axle.

 

[Mattchu60]

Everything I read says dump the TBI heads for Vortecs. Or are you suggesting the TBI heads so a computer calibration isnt required? Would a mild cam work without a re-tune?

 

[Jims86]

Everything I read says dump the TBI heads for Vortecs. Or are you suggesting the TBI heads so a computer calibration isnt required? Would a mild cam work without a re-tune?

Remember, most of what you are reading is from a top speed matter of opinion. People that buy a truck to try to race camaro's.
You should also be reading that TBI heads are perfect for towing and economy, both contributions of the swirl port design.
In the grand scheme, cheaper also.
Cheaper manifold, no external EGR to worry about, and no tuning headache.
Has to be tuned to use vortecs, otherwise, it runs ****** untill 2000 rpm. The best cam you can use are the close to stock choices...they give you the torque at the lowest possible rpm, anything bigger, and the max power numbers start to move up the powerband. Cant just throw in any cam and expect great results...it has to work together with the rest of the top end.

 

[bucket]

I'll stop in to gripe about exhaust manifolds... I think they suck. Poor flowing and they often will crack just as soon as a decent set of headers will rust. There, I'm done

 

[crazy4offroad]

I have to agree TBI heads are more low-end torquey while Vortecs show more top end difference. And I'll also agree once you address the gear ratio issue you may not want to do anything to the motor right away.

 

[Mattchu60]

This is good info, thank you to all that have responded.

So lets say i did this instead:

- reman TBI motor with rebuilt TBI heads
- TBI performer intake
- slightly off-stock cam, like the one Jim noted above or the 1st level comp cam
- still remove egr and AIR system, just for less clutter, less stuff to "go wrong" as well
- should I look into getting a 454 TB base? or just leave my 350 on on? Also I know that CFM makes a ported one which may be an option.

What kind of hp are we looking at? 220-230?

Also, what about tuning with the above? still need a tune or would I be ok on the stock setup?

 

[Jims86]

I'll stop in to gripe about exhaust manifolds... I think they suck. Poor flowing and they often will crack just as soon as a decent set of headers will rust. There, I'm done

No,no,no.....intake manifolds suck....exhaust manifolds blow.
Dammit, I thought you knew that!

I guess I have been lucky with manifolds, allthough all the reports I heard of cracking, were from guys who used gaskets. I never use gaskets.

 

[Jims86]

This is good info, thank you to all that have responded.

So lets say i did this instead:

- reman TBI motor with rebuilt TBI heads
- TBI performer intake
- slightly off-stock cam, like the one Jim noted above or the 1st level comp cam
- still remove egr and AIR system, just for less clutter, less stuff to "go wrong" as well
- should I look into getting a 454 TB base? or just leave my 350 on on? Also I know that CFM makes a ported one which may be an option.

What kind of hp are we looking at? 220-230?

Also, what about tuning with the above? still need a tune or would I be ok on the stock setup?

That is totally possible, you would need to have the egr flag in the chip disabled though, or you will get a light.But with the towing that you are doing, I would strongly suggest keeping the EGR to keep chamber temps down, and to keep cuurent timing tables.
With TBI heads, i had 230hp, and about 406 ft lbs.tq
The holly or 454 TBI will work, but you may need to have the manifold hogged out to match the 2" bores.

 

[bucket]

No,no,no.....intake manifolds suck....exhaust manifolds blow.
Dammit, I thought you knew that!

I guess I have been lucky with manifolds, allthough all the reports I heard of cracking, were from guys who used gaskets. I never use gaskets.

Lol oh yeah, I had it backerds.

I've only actually had one crack, it was in a few places and no gaskets were used. But I've seen oodles of other that were cracked. The biggest pain around here is broken/rusted downpipe studs. Sometimes I'd rather get a good kick in the nuts (or nut if I just had the one) than deal with those things.

Collector bolts rust right up too, but those you can just twist them right off and replace them. I get 6 or 7 years out of basic headers before they get holes in the primaries. The nice coated ones should last significantly longer. Even when they do need replaced, everything comes apart easy.