engine swap

[bowtie65]

i have a 90 k1500 4x4 5.7tbi needs a engine...whats the deal i can only use a 88-98 engine?? dose it matter what it comes out of truck or car..anything in that year is plug and play.....confused

 

[454cid]

96+ are the Vortec engines, you don't want those if you are looking for a direct replacement. The ealiest TBI engines may have been a bit different than the later ones, but I don't know the details.

 

[Schurkey]

i have a 90 k1500 4x4 5.7tbi needs a engine...whats the deal i can only use a 88-98 engine?? dose it matter what it comes out of truck or car..anything in that year is plug and play.....confused

Nearly any SBC short-block will fit, starting whenever they used the side mounts instead of the front mounts--'58 to current? The early Nova blocks had goofy oil filter mounts, but they might work anyway.

Crankshafts with the 2-piece rear main seal will need a flywheel or flexplate to suit. The OEM 1-piece rear main seal flexplates are known for cracking, if you use one be VERY careful to inspect it. I wouldn't put a used one back on--get a new one, and then have the engine balanced because the "new" aftermarket flexplates are not known for accurate balance.

The issue comes with the cylinder heads. The TBI manifold on your truck is set up to accept the two center bolts at a different angle than the two on each end--6 per side total. Vortec heads and manifolds use 4 bolts per side; the TBI manifold for Vortec heads is hyperexpensive.

So you're going to want to keep the original-style TBI cylinder heads, so you can use the OEM TBI manifold. Some folks (me, for example) convert to a carbureted manifold, use a TBI-to-Quadrajet manifold adapter, but then you've got EGR problems, vacuum port problems, heater-hose connection problems, accessory-mounting problems, etc.

The hot-rod upgrade for the OEM TBI cylinder heads is a Summit-brand set of aluminum heads using the TBI intake bolt pattern. I forget the part number. Add either hardened pushrods and use steel pushrod guideplates, or the OEM-style self-aligning rocker arms (but not both) Then you use the original TBI intake manifold, and everything bolts together nicely.

"I" would (and did) get a short-block that uses the spider hold-down for the roller lifter dogbones; 1986 and later. NOT using a roller cam is silly. But not all '86-later engines used roller lifters.

 

[PlayingWithTBI]

The hot-rod upgrade for the OEM TBI cylinder heads is a Summit-brand set of aluminum heads using the TBI intake bolt pattern. I forget the part number. Add either hardened pushrods and use steel pushrod guideplates, or the OEM-style self-aligning rocker arms (but not both) Then you use the original TBI intake manifold, and everything bolts together nicely.

Heads - SUM-162108, $1099.99 (comes with guide plates)
Chromoly Pushrods - SUM-1457900 (measure for your application, YMMV), $104.79
Rod Length Checker - TFS-9001, $17.99
Full Roller Rockers - PRO-66929C (1.6 ratio), $188.99

HTH

 

[454cid]

So you're going to want to keep the original-style TBI cylinder heads, so you can use the OEM TBI manifold. Some folks (me, for example) convert to a carbureted manifold, use a TBI-to-Quadrajet manifold adapter, but then you've got EGR problems, vacuum port problems, heater-hose connection problems, accessory-mounting problems, etc.

Does that actually flow better than a TBI manifold? I do like the look of the earlier TBI.... I looked at a early L19 454 this summer.

 

[Frank Enstein]

Your intake manifold will bolt up to 1987 to 1995 heads with the exception of Aluminum L98 Corvette and LT1/LT4 heads.

Blocks from 1987 and newer can accept factory hydraulic roller cams and lifters but may need holes drilled and tapped.

Blocks from 1986 and newer are one piece rear main seal and will accept the same flywheel/flexplate you have now.

Blocks prior to 1986 use a two piece rear main seal and will need the correct flexplate/flywheel to match.

A hydraulic roller cam is a very good option. If you can make it fit in the budget.

 

[Frank Enstein]

Here is a document I wrote up that may help that may help.


A Brief History of Small Block Chevrolet Cylinder Heads


1st Design 1955 to 1986

Perimeter Bolt valve covers.

Top valve cover bolts are closer together than the bottom bolts on 1955 to 1958 heads.

Six intake manifold bolts per head 90 degrees to the gasket surface.

Many heads made prior to 1972 Have no accessory holes.


2nd Design 1987 to 1995

These are NOT Vortec heads.

Center Bolt Valve Covers.

Six intake manifold bolts per head center two straight up.

Front and rear bolts remain 90 degrees to the gasket surface.*

*Exception 1987 to 1991 Corvette Aluminum (L98) heads

retain the 1955 to 1986 bolt pattern For the intake manifold.



3rd design 1992 to 1997 LT-1/LT-4

Center Bolt Valve Covers

Six bolts per head for intake manifold 90 degrees to the gasket surface.

No water or exhaust crossover passages "Dry Intake Manifold".

LT-4 has raised intake ports.

Raised "D" shaped exhaust ports.



4th design 1996-1999 Vortec Truck/ up to 2002 in Vans

Center Bolt Valve Covers

Four intake manifold bolts per head all straight up no bolts in the center.

Raised intake ports based on the LT-1/LT-4 design.

No exhaust crossover provision.

Conventional square port exhaust.

 

[Schurkey]

Does that actually flow better than a TBI manifold?

My issue was that I ruined one TBI cylinder head; and I was not going to spend any money on swirl-port nonsense. I have heard--but never verified--that the TBI manifold has mixture-distribution problems. Truthfully, that's not something I'd expect as it would create emissions problems--some cylinders lean, some cylinders rich would make for exhaust emissions trouble.

I already had a set of used 'n' abused aftermarket aluminum heads "on the shelf" that I got from eBay years before; but the center intake manifold bolt angles are wrong for the TBI manifold. I also happened to have a couple of used ZZ4-style intake manifolds (also an eBay purchase.)

So I touched-up the valve job on those heads, slapped 'em on a Vortec short-block with some mods, which meant I needed the ZZ-style manifold, and it almost fit together properly. The EGR gave me the most problems. There is nothing to bolt the brace from the rear of the A/C compressor to. And I had to fabricate some other items that weren't too difficult--cutting and bending the brake booster vacuum tube, adding a small bracket to get the coil mounting to line up with the coil mounting bosses cast into the manifold. Running a tap into the quick-coupler for the heater hose, and using brass fittings to connect to the manifold port.

The ZZ manifold and thin adapter plate for the TBI put the throttle body maybe a quarter-inch higher, and a quarter inch farther forward on the engine. The existing throttle cable would connect, the existing cruise control cable connected, and with some readjustment, the trans TV cable connected. I had to pull some fuel hose forward by loosening the clamps on the frame, tugging the hose, and then reattaching the clamps.

I'm still getting code 32--EGR problems, and I haven't figured out what's wrong there. It all "should" work. EGR valve was new in the last year or so, vacuum system verified then. Maybe something else has failed.

And I need to jack-up the fuel pressure, I think.

That may all happen before winter, but right now I have the rear brakes apart to replace a wheel cylinder and an axle seal; I want to verify the Gov-Loc in the differential, and I need to do "something" with the O2 sensor. I think the wire burned on the header...again.

For the record, the earliest TBI 454s used a carb intake manifold, with a tall TBI-to-Quadrajet adapter with a coolant passage cast into it. The hot "coolant" warmed the TBI unit in the same way that the coolant passage under the small-block manifold warms the whole manifold. I originally expected to use that adapter, but it put the throttle body way too high. I got a plate-steel adapter from...TransDapt, maybe. Perhaps 3/16 inch thick. Hardly enough to cut coarse threads in.

 

[L31MaxExpress]

I have slotted the center bolt holes to run a factory TBI manifold on older heads several times. Added tapered shim washers to get the bolts to apply even pressure to the manifold.

 

[Schurkey]

I have slotted the center bolt holes to run a factory TBI manifold on older heads several times. Added tapered shim washers to get the bolts to apply even pressure to the manifold.

That was my original plan. I looked at my TBI manifold, and it didn't seem viable to oblong the holes. The casting has thinned sections where the oblong would go; I was concerned about strength.

But you've done it, and it worked. That would have saved me a LOT of fabricating, and I'd have some place to bolt the AC compressor brace.

I've heard of grinding manifolds the other direction--putting older manifolds on newer TBI heads, instead of putting TBI manifolds on older-style heads. That appears to be entirely feasible, as long as those tapered shims are used. I have an old-style manifold already ground out for TBI heads, but I didn't figure my pickup needed a cross-ram intake.