[dfarr67]

I'm following with much interest, because I'd like to build something similar for my '89 TBI truck. I have a nearly new Edelbrock MPFI setup, would that flow enough air with the TBI throttle body to feed a 496 to 4000 rpm for towing? Using the MPFI deal would allow use of the OE computer which could save a lot of work or $. It has the larger injectors intended for use with a 502, that's why I have it, it didn't work right on a 454.



I have 2 sets of heads on hand, a pair of 3989241 and a set of Truck 3983136 castings. Both oval port, the truck heads are sort of closed chamber, CCs unknown ATM. Would either of these be a good choice?



Would the MPFI small port manifold work OK with oval port heads? If not, would a larger oval port manifold with bungs for the injectors work with the TBI TB or would a larger TB be needed?



I have a NOS set of Doug Thorley long tube Tri-Y headers for the truck - single outlet for the cat.

It's very easy to get that TB opened up a bit and bushings installed. Forget about the supplied Edelbrock chip and have it tuned properly- or as mentioned a proper ecu with good drivers. I had this system years ago on a vortec 350- wish I knew about tuning then....it's a good EFI.

 

[Collinsautomotive]

For my 89 truck with 7747, Edelbrock ran 4/4 injectors, my only problem was poor splicing but I heard others had driver problems. DynamicEFI makes a pnp 7747 among others that is specially modified with a 'port' mod, been runningit for years with several sets of different injectors- my tuning skills are crap however.

dynamic efi is nice setup

 

[Yoyodyne]

Yoyodyne:

Not sure what you are thinking here but you need to get back to a better starting idea.

I'm looking for simple inexpensive and effective. NOT trick, not cool, not high tech, not to impress anyone. Use available parts if possible.



The engine in this truck is at the end of it's life and needs redone. It towed my 43' GN fine when new, now it's worn out, and I'd like more power to make it easier to drive. I don't want to do a diesel swap, don't want an 8.1L, want to keep my T400 and GVOD. Want to make it as easily serviceable on the road as possible.

First none of those BBC head casting numbers are correct?

Here are the casting numbers with a corresponding chambers, what do you make of them?


First one looks like 3939241 in the photo but that doesn't come up in google.

Second if you are going to spend that much money and trouble trying to put an old technology "Edelbrick" semi -efi system and remain with a stripped down TBI throttle body only you are wasting money and not getting any real towing "bang for your buck"!

I would not put any money in to old iron BBC truck heads done right when you can buy a nice set of new or completely reworked Vortec small chamber heads for less than you will put making an old set of truck heads work! They add compression WHICH YOUR 89 454 TBI NEEDS BADLY!

To go 496 I need to buy pistons anyway, why not buy the pistons I need to get the correct compression with whatever heads I use?

The headers would be a nice addition since you already own them.

All I can say if you're a wise man and want to make an older 1989 TBI truck work for TOWING, keep it simple, follow something like I laid out on this post and don't try to get torque and towing performance putting all sorts of big dollars into expensive EFI systems and engine conversions and builds, when the cost of these types of conversion would probably exceed the value of the truck.

JMEXPO

I already own all the stuff I described except for a crank and pistons. I'll also need a cam regardless. I think new AL heads fit that big dollars category.


What is it about the MPFI that makes it worse than the stock TBI?

 

[Yoyodyne]

Yeah, the "let's do a whole alum topend" on the $5000 truck is great idea, but just not worth it $$$ per hp gained. Bang for buck, E-brock tbi intake, home port it, find a big bore TBI for it(there used to be shop that made super big ones, but I think they shutdown), chip it/tune it and 3in single exhaust w/ good plug wires. Done. The headers will drive you out of your mind w/ exhaust leaks, even with good gaskets. If there is a set of higher ratio bolt on rockers, do those too. IMO pulling the heads off is a waste of time unless you absolutely love the truck. If you do really love it, a Cummin's or Vortec swap is best $$$ spent long term

Dave gets it. I'm not building a hot rod. I need a new motor, this one leaks more than it burns. I can do a crate 502 or do a 496 for slightly more than the cost of a rebuild and use up some the the parts I already have. If I can get another 80 - 100,000 miles out of it reasonable cheaply then either I'll buy a diesel Megacab or I won't need one at that time.


The truck already has a Edelbrock TBI intake manifold (only because the stock iron manifold cracked) a 3" exhaust and other than the worn out motor it suits me just fine. Doing a Cummins swap to my satisfaction would cost more than doing this motor and I really don't want a diesel. i don't want a Vortec or a 8.1 because I don't want to have to take the truck back home to the shop where it was built when something fails along the interstate.

 

[Rapidray]

Yoyodyne

Based on your last more complete information and explanation, I can give you one more simple recommendation.
Take your existing block, buy a complete 496 rotating assembly off of eBay @$1500, buy the Edelbrock RPM heads complete @975. Take the block, kit and heads with a good gasket kit to a good machine/rebuild shop and have them build you a nice 496 long block. Install a nice hydraulic roller camshaft like the number from Comp I listed earlier in the post. Install your Edelbrock Mpfi kit you already own, bolt on your headers, drop it in the truck, change the fuel pump, put a nice tune on it and you will have a nice reliable high torque engine for towing.Nothing exotic just a nice engine for towing and about as inexpensive as a GOOD BBC 496 engine can be!This engine should make an easy 475 Hp and 500 lb/ft of torque @3800 rpms. Your existing 454 probably made 260hp when newer and about 325 lb/ft of torque for comparisons.
Take those ugly old iron truck heads you have, take out a valve on each head,loop some chain thru them and use them for boat anchors!
You are going to spend about $4K to $5k doing this right with the parts you have, the machining, assembly and parts you need to purchase. If you can and will spend about this you'll do fine, if not then your kidding yourself on what you need to do. JMHO
Good Luck!

 

[Yoyodyne]

Got it Rapidray, thanks. ~$!000 for a pair of heads is cheap, I was thinking it was $1000 per head. But I can't find 60496 Edelbrock heads, am I looking for the right number?



Are these oval port heads? Will the small port intakes work OK on oval ports? I've heard both yes and no. And how much compression can you safely run on 87 octane?

 

[Rapidray]

Sorry, screwed that up on the Edelbrock heads, $975 each or about $2K a pair.

The Flo-tek 290cc oval ports aluminum about $1500 a pair are the best bang for the buck new.

The Flo-teks also have a 112cc chamber which will raise your compression to about 9.0 to 1 with correct head gasket.

Good tune on the EFI and it will run ok on 87 with the 10% ethanol mix.

 

[DualQuadDave]

Dave gets it. I'm not building a hot rod. I need a new motor, this one leaks more than it burns. I can do a crate 502 or do a 496 for slightly more than the cost of a rebuild and use up some the the parts I already have. If I can get another 80 - 100,000 miles out of it reasonable cheaply then either I'll buy a diesel Megacab or I won't need one at that time.


The truck already has a Edelbrock TBI intake manifold (only because the stock iron manifold cracked) a 3" exhaust and other than the worn out motor it suits me just fine. Doing a Cummins swap to my satisfaction would cost more than doing this motor and I really don't want a diesel. i don't want a Vortec or a 8.1 because I don't want to have to take the truck back home to the shop where it was built when something fails along the interstate.

Ok, I did not realize you were building a whole motor, thought this was just an upgrade deal. If you are building, just go as cheap as possible. Everyone is going to tell me I'm wrong, but I would just pocket port the stock peanut heads, shave them .020, put the cheapest-cheap shit cast pistons in it. Find a thin head gasket for it, something in the .020-030 range. Comp makes a TBI Cam or at least used to, call them. IMO doing alum heads on any TBI motor is a complete waste. I remember a 454SS that a friend of mine worked on back in the late 90's. Had ported aftermarket heads, a Whipple blower, cam, you name it....and a stock TBI strapped on the back of the blower. Was always slow for what it was. He sold the truck and the next guy put a carb on it and went like 2 seconds faster, lol. TBI= don't waste money on it.

 

[Yoyodyne]

A good towing spec. cam for this use is a Comp Cams part #11-412-8 grind # 266HR-12.Available from various suppliers for about $275 -300 per cam.
This cam will produce the most torque between 1500-3800 rpms which is where you want it for towing. With this cam you will be able to tow in many areas in OVERDRIVE between 55-70mph! This is ideal for towing and mileage!

Do you have a recommendation for a cam from someone other than CC? Or this cam with other lifters?

 

[Yoyodyne]

Or just use this cam with other lifters?

 

[Rapidray]

Anyone of these will make a good camshaft choice for your truck engine build

Crane - 168721

Elgin - E-1234P

Erson - E120203

 

[DualQuadDave]

Or just use this cam with other lifters?

Use any hyd. lifter you want to with it. Don't feel restricted to having to use all Comp components. If you want something custom and "a little more" I can spec a Bullet or Cam Motion cam for you. General rules of TBI are stay close to factory intake duration, run as much lift as you can get away with cheaply, run as much exhaust duration as necessary to make some power and keep the chamber a little cooler at cruising speed and keep the lsa 114 or more, or at least have no overlap. RRay recommended some good ones, also, but I do not recommend the Elgin w/ the 112 lsa. TBI needs a super strong vacuum signal to function right. Not worth the possible driveability loss for the power difference.

 

[Collinsautomotive]

tbi just needs a early ivc to stay happy, just like a carb motor

 

[Collinsautomotive]

Dave gets it. I'm not building a hot rod. I need a new motor, this one leaks more than it burns. I can do a crate 502 or do a 496 for slightly more than the cost of a rebuild and use up some the the parts I already have. If I can get another 80 - 100,000 miles out of it reasonable cheaply then either I'll buy a diesel Megacab or I won't need one at that time.


The truck already has a Edelbrock TBI intake manifold (only because the stock iron manifold cracked) a 3" exhaust and other than the worn out motor it suits me just fine. Doing a Cummins swap to my satisfaction would cost more than doing this motor and I really don't want a diesel. i don't want a Vortec or a 8.1 because I don't want to have to take the truck back home to the shop where it was built when something fails along the interstate.

I'd just buy a crate 502 and the Edelbrock intaoe should fit, call me or someone else who can do a chip, upgrade the fuel pump and enjoy

 

[Yoyodyne]

Thanks everybody for the info. And to the OP, sorry for the thread hijack.

 

[Yoyodyne]

I'd just buy a crate 502 and the Edelbrock intaoe should fit, call me or someone else who can do a chip, upgrade the fuel pump and enjoy

How does the cam in the HT502 compare to the cams listed above?

 

[427f2]

How does the cam in the HT502 compare to the cams listed above?

The HT cam is I204/E209....... I.480/E.483 112lsa
Flat torque curve to 3600 and starts to roll off after 3600.
IIRC HP peak is at 4200.

Pretty wimpy cam and you could likely pick up a bunch with something
better as long as you have a way to tune the ecm.


Chevrolet Performance HT502 long block crate engines offer tremendous value and performance. They're based on the Gen VI 4-bolt mains with one-piece rear main seal blocks.

Features include:

* Approximately 8.75:1 compression
* 406 hp at 4,200 rpm
* 541 ft.-lbs. of torque at 3,200 rpm
* 4.000 in. stroke, forged steel, externally balanced crankshafts
* Forged steel connecting rods
* Forged aluminum pistons
* Hydraulic roller camshafts with .480 in. intake lift, .483 in. exhaust lift, 204 intake and 209 exhaust duration at .050 in., and 112 degree lobe centerline
* Cast iron cylinder heads with oval port 118cc combustion chambers
* 275cc intake runner volume with 2.07 in. intake valves and 1.73 in. exhaust
* Configured for 3/8 in. thread 7/16 in. shank rocker arm studs
* Stamped steel, self-aligning, 1.7:1 ratio rocker arms
* ACDelco spark plugs
* Oil pans
* Black powdercoated aluminum valve covers and timing covers
* 8 in. harmonic balancers
* 14 in. automatic flexplates

 

[G-Code]

Any of you guys with on the header swap ever use the mid-length Tri-Y's by Doug Thorley ?

 

[Yoyodyne]

The HT cam is I204/E209....... I.480/E.483 112lsa
Flat torque curve to 3600 and starts to roll off after 3600.
IIRC HP peak is at 4200.

Pretty wimpy cam and you could likely pick up a bunch with something
better as long as you have a way to tune the ecm.

That brings me full circle back to why I wanted to build a 496 - For less dollars I could have bigger heads and a better cam.

 

[MN Hemi]

Biggest improvement I’ve seen personally is dropping the antifreeze and running straight water with Water Wetter. My 1988 TBI will run 220° and get a gutless 5 mpg with 50/50 anti freeze. With water/Wetter, it goes like hell and gets 7-8 mpg.
I have a stock engine, Edelbrock intake and headers, GMS spacer, and a dual snorkel air cleaner that I made.

It’s a gutless gas sucking turd at high engine temp. The computer adds fuel and pulls timing. It’s horrible. Cool it down, it’s an animal. 19,500# loaded and runs like a pack of ass. I love that truck, 1 ton 2wd, 3x3 duallie. 28’ trailer.