Recommendation on Swapping a 4.8L LR4 LS Engine & 4L60E Trans right into a Firebird Mission

Recommendation on Swapping a 4.8L LR4 LS Engine & 4L60E Trans right into a Firebird Mission


I’ve a 1969 Firebird that I’m swapping in a 2002 LR4 4.8L LS engine from a GMC Sierra pickup. I’ve the mechanical swap components for mounting the engine however I’m on the lookout for a finances technique to management the spark and gas. I additionally want some technique to management the 4L60E truck trans that got here with the engine. Plus, I wish to run an LS6 consumption. What’s one of the best ways to do all this?


The obvious method can be to re-use the present ECU and wiring harness. You didn’t point out whether or not these components got here with the engine. Sadly, it’s a little bit of a danger buying a used harness and ECU with no assure that these items will work. And should you resolve to alter some components (like upgrading to a efficiency LS camshaft), this may require the expense of a customized tuner to make use of software program like HP Tuners to make the required idle and part-throttle adjustments to assist the engine run its greatest.

Discover the Proper Engine Management System

This leads us to an alternate path to get the place you wish to go. That might be a Holley Terminator-X Max EFI system on your 24x LS engine. The Terminator-X Max will management each spark and gas and likewise consists of transmission management. The Terminator-X equipment comes with an entire ECU, wiring harness, and a hand-held display that permits the consumer to enter all the information and do easy tuning with out the necessity for a laptop computer. It’s a easy conversion and also you solely want the hand-held as an alternative of a laptop computer though you should use a laptop computer should you so want. The injector harness may have wiring harness adapters to hook up with the inventory LR4 truck injectors.

This lets you use a manufacturing unit passenger automotive manifold just like the LS6 consumption as a result of that truck manifold in all probability is simply too tall to clear the inventory hood, though that may require a distinct passenger automotive accent drive because the LS6 throttle physique will hit the truck water pump higher radiator hose connection.

On the time of this submit, the Terminator-X Max is rather less than $1,500 which appears like some huge cash however when you think about that this may plug proper into the present engine (together with the digital drive-by-wire throttle), all you would need to do is add an digital throttle pedal to your 1969 Firebird and plug within the harness. The Terminator-X Max additionally makes use of a wideband oxygen sensor for suggestions air-fuel ratio management that you just set with the hand-held tuner. Inserting the O2 sensor within the exhaust would require some customized welding however any muffler store can do this for you.  

Updating the Gas System for EFI

Additionally, you will should spend a bit of bit extra money to transform to a return type gas supply system. We’ve had actually good success utilizing Holley’s Sniper tank and pump meeting they usually supply one particularly for the early F-body. The equipment is simple to assemble and replaces your present tank with a model new stamping that has been powder coated. The one different factor you would need to do is add an digital throttle pedal however maybe you’ll be able to pull that from the truck that donated the engine.

The swap to a passenger automotive type manifold is a good suggestion since, as we talked about, it’s doubtless the truck manifold is not going to match below the flat hood of a ’69 Firebird. The LS6 consumption is turning into tough to search out however related efficiency might be had with an LS2 consumption for a cathedral port engine. There’s an AC Delco passenger automotive alternative manifold for cathedral port heads that’s inexpensive. We’ve listed its half quantity within the following chart. This may require injectors, a throttle physique, gas rails, and bolts to finish the set up however at the least the fundamental manifold is inexpensive at below $150.

Contemplate the Carbureted Route

As a result of the 4.8L engine is a bit of quick on displacement, we’d suggest a twin aircraft consumption. Within the components checklist we’ve included all the foremost components you’ll want to put in the consumption, carburetor, and an MSD spark controller. This may deal with the gas and spark necessities however you’ll nonetheless want a separate field to manage the 4L60E transmission. We’ve had actual good luck with the Compu-Shift Professional controller. We’ve additionally listed different controller choices such because the MSD Atomic for the 4L60E however there are different corporations together with Edelbrock, Painless, TCI and others you may examine.

One benefit of the carbureted system is that you’ll not be required to utterly convert the gas supply system however you will have so as to add an electrical gas pump to feed the 4.8L engine since LS engines supply no provision for a mechanical gas pump.

We totaled the costs of the whole carbureted gas system and in contrast that to the price of an entire Terminator-X Max and we discovered that the 2 are considerably related—though the EFI model can be barely larger should you embody a alternative consumption manifold. After all there could also be some cash to save lots of on the carbureted aspect if you have already got a carburetor, which can save about $500.

Nevertheless, with the carburetor you hand over suggestions management of the air/gas ratio, in order that you’ll have to tune the air/gas ratio manually in the old fashioned custom of fixing jets and doubtless the idle circuit since that little motor will want much less gas at idle.

We’d are inclined to aspect on the EFI aspect of this equation however there are definitely benefits when it comes to simplicity with the carburetor. The perfect a part of all that is the number of choices.

LS-Swap 1969 Firebird Components Record

  • Holley Terminator-X Max, 24x, 4L60E management – HLY-550-916
  • ACDelco GM Real Components EFI Consumption Manifold – ADO-89018187
  • Holley LS Mid-Rise Carbureted Consumption Manifold – HLY-300-130
  • Holley 4160 750 cfm Carburetor – HLY-0-3310C
  • Edelbrock TC Transmission Controller – EDL-36212
  • MSD 6LS Ignition Management Unit – MSD-6014
  • MSD Atomic 4L60E Transmission Management Module – MSD-2760
We’ve truly carried out the conversion you’re contemplating with a 4.8L engine utilizing a 200-4R trans slightly than a 4L60E in our 1966 Chevelle. The small displacement engine lacks off-idle torque however runs sturdy after 3,000 rpm. We added a 150 hp shot of NOS nitrous to assist it off the beginning line and ultimately pushed this little motor to mid 11s at virtually 120 mph! (Picture/Jeff Smith)

Jeff Smith has had a ardour for vehicles since he started working at his grandfather’s fuel station on the age 10. After graduating from Iowa State College with a journalism diploma in 1978, he mixed his two passions: vehicles and writing. Smith started writing for Automotive Craft journal in 1979 and have become editor in 1984. In 1987, he assumed the function of editor for Sizzling Rod journal earlier than returning to his old flame of writing technical tales. Since 2003, Jeff has held numerous positions at Automotive Craft (together with editor), has written books on small block Chevy efficiency, and even cultivated a powerful assortment of 1965 and 1966 Chevelles. Now he serves as an everyday contributor to OnAllCylinders.


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September 2022