Hey guys or girls I have a ? for you .Well my 1984's engine is shot so im going to replace it now My ? is I have a 1991 chevy van with the 350 engine in it.Now will this engine work with my cross fire set up or do i have to change out parts.Please let me know i miss driving her

 

Should work just fine! However, you have to use the flex-plate (flywheel) off the new engine. (assuming auto trans.)

 

Yes its a auto trans so thats it Change the flywheel and flex and it should be good to go.Well thanks for info.Also do you know anyone looking to by a hummer replica i have a sweet one on ebay -PLUG

 

If the van has a throttle body on it, you will have to change the cam in it, or it will run like a stone. Single throttle body cars have a computer specific cam.
If you are going to all the trouble to change the engine, why not change the fuel injection as well, and get some more kick to that gas pedal?
I have a complete fuel injection set-up for an 86 that gives you computer, harness, all sensors, later exhaust, and all the goodies to make it run way better.
includes cam, distributor, throttle body, injectors, ignition module, etc.
it even includes the firewall harness feed through and the lights, alternator, smog, etc. is already in the harness
asking $1000 for everything
one plug deserves another one

 

The long block will work fine but you may have to re-plumb the crankcase vent and EGR due to the center-bolt valve covers on the van motor. Also, the cam in the van motor will be very mild and the valves are most likely much smaller. The van motor will probably be much lower compression so don't expect the same level of power that the old L83 provided.

If you are thinking about freshening up the van motor, have a machine shop do a good 3-angle valve job on the heads and knurl the valve guides. Check the crank and all of the crank and rod bearings for any indications of wear. I would also install a new oil pump.

Use all of the brackets and accessories from the L83. It would be a good time to get a new water pump, thermostat, distributor cap and rotor, plugs, wires, hoses, and belts. Check the belt tensoner and idler pulleys and replace as needed.

If your 84 is a manual tranny car, you will need to add an input shaft bushing in the rear of the crank.

 

Oops, forgot about the different heads:o, It would be easier to use your old ones, the center intake bolt holes ARE different.

 

I don't know what engine comes in a '91 van. If it is a vortec the heads won't work. If it is not a vortec, then there are 4 bolts between the intake manifold and the heads that will have to be dealt with. On the 1986 and up, non-vortec, iron, heads, the two center bolts on each side are vertical, straight up and down, rather than at the same angle as the other bolts. The hole can be re-drilled or reamed, but a wedge will have to be made or some other provision made for the bolt head to land on a flat surface.

Don't, I repeat, DO NOT spend a nickel, let alone a thousand dollars to swap over to a TPI system. It is a lot of money and a lot of work, all for no gain in performance. The manifold fitment situation is the same with the TPI manifold as it is with the Crossfire, so it doesn't even save you that hassle.

The 1984 Crossfire cam is pretty mild. The '84 ECM would have no problem dealing with the '91 engine as is. You might take the opportunity to up grade, if you like.

As mentioned, you will need a 1986 and up flywheel or flex plate, whichever your car uses. Make sure the damper on the front of the engine is no larger than 7" in diameter to clear the front cross member. Use all the 1984 accessories and sensors in the same locations they were in on the '84, and it should be a simple bolt in.

RACE ON!!!

 

I've done this conversion (almost). In my case, my car was an '83 Trans Am, and the donor motor replaced a 305 CFI. My donor motor was an '88 Truck TBI engine but that is IDENTICAL to your donor vehicle's engine. CFI-EFI is right about the center intake-to-head bolts; on your donor engine, they are vertical and on your original engine they are at ~45* angle (perpendicular to the intake mating surface on the head). When I did this swap, I simply used a diegrinder to grind a flat, horizontal pad into the existing bolt hole flange or bung that's cast into the intake. There was enough material there to do that and it worked fine and never leaked.

I second what was said above about swapping to TPI; not worth the money.

The '84 ECM will deal w/the truck long block fine. It's even MORE conservative than your original long block. Read on...

Your donor engine is the swirl port, TBI 350 with what is refered to as a "peanut cam". Less than 200* on both sides and less than .4" lift also. SUPER lame cam. The heads in stock form are worthless for developing any kind of power, as half the intake port is blocked off by the intake valve guide (as cast) to promote swirl. That engine w/stock CFI, headers and optimized timing and fueling is good for about 230 hp at the crank at MOST. In other words, swapping in that long block, you'll lose power due to a smaller cam and worse heads. It will run and function fine though.

In my T/A, I got a 14.6 @ 95 out of that same combo (and headers) w/a 5 speed and 3:42 gear, in a 3200# car. That's about 220-230hp. i'd look for another long block, OR reuse your heads and slap in a $90 Summit cam.

 

I dont care for the loss of power i just love to drive the car.Now if i change the heads from my vett to this engine i should have no problem with it running? Now some of you are saying have the cam change or have the heads done over but with all that work i would just rebuild the vett engine im looking for a cheap way out on this one. Thank you all for all the help Shawn

 

For cheap, assuming everything is up to snuff with the truck engine, leave the heads and cam on the truck engine alone and just swap it in using the Crossfire intake as Tom400CFI outlined. Install all the Crossfire sensors in the same locations they were in. If BOTH the car and the truck are autos, use the truck flex plate. If the truck damper is bigger than 7" you can swap the one from the Crossfire onto the truck engine. This is about as simple as a conversion, if you can call it that, gets.

RACE ON!!!

 

First off, define "shot". Is your engine burning oil? Knocking? Block cracked? Rod dangling out of the oil pan?

What I'm getting at, is why not just rebuild the old engine? Is this an issue of cost and the van engine is free? An issue of time where you want as little downtime as possible? Combination of the two?

You could just pull the engine and have a machine shop give you an estimate on rebuilding it. It's a small block Chevy...nothing mysterious about it. And a basic rebuild shouldn't be terribly expensive. Or if you don't want the downtime, a basic LM1 crate engine will get you back on the road.

As everyone above mentioned the van engine will work....but I have doubts as to how satisfied you're going to be with the result.

 

Well the vett engine has a bad knock and the van engine is free with super low milage.Now to rebuild my engine its about 1.200.

 

Sounds like a good reason to use it.

You can always put the van engine in, and mothball your original engine in the shed somewhere. Down the road when you find the $1200 in your sock drawer, you can rebuild it then and swap it back in.

Good luck with the project.

 

So what do you think just change my heads from the vet to the new engine.I dont want to grind and rig this engine in i just want it to run.

 

Hi, changing the heads is a looking ideal vette heads provide better air flow. Larger too. But remmeber the extra miles on the vette heads vs the low mileage on the van heads. Are they the small year? Good luck

 

What are you doing wit the all engine? where is it as far as location? City? are you looing to sell it?

 

Since the OP said this:I'd recommend this:I'm betting that the amount of peak hp that he loses won't even be noticed. Torque in normal driving will be the same -or close enough.