4.9L Cadillac Information (Page 1/11)
Reborn756 AUG 09, 01:32 AM
Howdy folks, Darryl here again. This time, with an engine question.

I've been doing a lot of research on the 4.9L Cadillac. It's really starting to look like this is the engine for me. I however, did have a few questions, both about the engine, and the procedure to swap it into an 88 Formula.

- How much fab work is involved with getting a 4.9L to fit into the 88, and to get it bolted to the cradle?

- How much power are you guys actually getting out of the engine?

- What performance modifications are you doing to the 4.9L? Is it viable to get a set of headers on one of these with it squeezed into a Fiero?

- Has anyone had a custom machine shop build a set of Aluminum heads for this engine? If you actually did, what was the cost, how much weight savings was there compared to the iron heads, and how much power (if any) did you gain?

- Has anyone reliably hooked a turbo up to a 4.9L without turning the engine, or the TH440T4 into a grenade?

- What fuel mileage are you seeing from the 4.9L? City/Highway, Driving with grandma in the passenger seat/ showing off to the pretty neighbor girl?

- Has anyone ditched the factory fuel system for a Q-Jet, and has anyone ditched the factory fuel system for an EFI, like the Sniper, Fi-Tech, or MSD EFI? What were the results from each fuel delivery system, including factory?

- What advice can you give regarding the swap, be it tips on making it easier, making reliable power, parts to stay away from, etc?

Thanks in advance for your time folks, I do appreciate it!

P.S: Here's a picture of the car I'm planning on buying, so you guys can finally see what I'll be working with!

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- Darryl

Will AUG 09, 05:17 AM
I haven't done a 4.9, BUT...

The engine is lightweight, cheap, compact and a relatively easy swap.
If you want a lot of power, it is *NOT* the engine for you
The heads are atrocious and will always be choking the engine from actually breathing.

A one-off custom set of billet aluminum heads (because that's how a shop could make just one set) would be a $10,000+ investment to pay for the design time and production.

PBJ turbo'd a 4.9 and ran it with a built transmission. That car drove well into the 12's, but was all launch with a low trap speed.

There was a user who made outrageous power claims regarding his builds which used a carb on the original TBI manifold... I don't think anyone who knew anything ever believed him.

Any ECU that can control a distributor Chevy can control the 4.9... The 4.9 is actually better in that regard than factory distributor Chevies, as it the cam synch for sequential injection in the distributor.
Warlordsix AUG 09, 08:02 AM
If you want a car that handles well, is fast stoplight to stoplight, turns heads by the sound alone, and is very practical in the Real World, then the 4.9 easily fills that bill. I like mine so much, I picked up a second, low-mile 4.9 and have it setting in the garage, so I can do a second build.

The engine puts out a lot of torque down low in the powerband, so launches are great, and passing on the highway is a matter of just pressing the foot...no downshift necessary. The sensation is just a great, low RPM shove against the back. For this next build, BTW, although I'm happy with the Caddy ECU, I will likely run a F.A.S.T. Multiport ECU....comes with a harness, too, and the whole shooting match costs no more than having a custom harness made.

The engine weighs just 10lbs more than the 2.8 it will replace.

Intakes for carbs, headers, etc., are all made by http://johns49performance.com/index.html

Also, 4.9 engines are plentiful and inexpensive....but, of course, you'll prefer to find a low-mile unit. Nevertheless, plenty of high-mile 4.9s still run well. Reliable.

Ernie

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'87 Fiero 4.9 5-speed

[This message has been edited by Warlordsix (edited 08-09-2020).]

Raydar AUG 09, 10:07 AM

quote
Originally posted by Warlordsix:
...

Intakes for carbs, headers, etc., are all made by http://johns49performance.com/index.html




John is also doing engine mounting brackets that, I believe, are a bolt-in to the cradle. (My installation was done, years ago, with fabricated brackets welded to the cradle.)

The Caddy 4T60E trans is a well documented swap into the Fiero. Just a couple of brackets are needed. Or you can do a manual. Pretty much bolts right up, with a few specialty pieces. (The manual gearing is way less than optimal, but it's still a complete blast to drive. The Caddy automatic doesn't do anything quickly.)
I would recommend that you reinforce your cradle, where the front engine bracket and the front trans bracket are bolted. The 88 cradle is notorious for cracking and having mounts tear loose, on the front side.

You can gain a few HP (the general consensus is +20, but it's not really been proven back-to-back) by adding an Allante intake setup. But they're becoming as uncommon as chicken lips.
John is also in the process of tuning a short runner intake bolted to an Allante base. We'll see how that works out.

With my manual trans, the best I'm getting is around 25 MPG, on the highway. Driving "around town" in mixed driving. I get ~19-20.

This is the regular Allante setup, bolted to a 4.9. Complete with "hot air" intake.

[This message has been edited by Raydar (edited 08-09-2020).]

Reborn756 AUG 09, 10:39 PM
Thanks for all the info so far folks, I do appreciate it!

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- Darryl

Will AUG 09, 11:38 PM
And Max Cubes installed a blower on a 4.9... I think the car got wrecked before he was able to do much with it, though.
Raydar AUG 10, 05:16 PM

quote
Originally posted by Will:

And Max Cubes installed a blower on a 4.9... I think the car got wrecked before he was able to do much with it, though.



True! I forgot about that. That thing was a potential beast.
Dennis LaGrua AUG 10, 05:34 PM
My view on the 4.9L upgrade is that it provides the best torque for the cost. On a DIY install you can get it done for about $1500. The challenge is to find a relatively low mile engine. Its fast with the auto if you change the 4T60e sprocket and chain to give to a 3:33: FDR
.
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 08-10-2020).]

Reborn756 AUG 10, 11:49 PM
I just emailed a company regarding a custom set of aluminum heads for a 4.9L Cadillac engine. Waiting to hear about pricing and their input on if they think a set of Aluminum heads would be of any real benefit in an application like this. I've heard from numerous people that the heads are incredibly restrictive, so maybe a custom set could really liven it up?

Also, there's obviously a weight savings to be had here, though how much is hard to tell. Those of you with a 4.9L, did you ever weigh the heads to see how much of the weight came from just them? I'd suspect we could shave, I don't know, 15 pounds off per head by going aluminum?

As Will mentioned, I'm probably looking at an astronomical price to have heads made. But, I plan on keeping the Fiero until I'm under the ground, so to me the money would be well spent, getting the car set up exactly how I want it. And who knows? Maybe a company having all the files needed to machine these heads would help other folks out in the long run, would cost a lot less to get a second set done considering all the AutoDESK files will already be done.

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- Darryl

Will AUG 11, 08:13 AM
If the bore center is similar to an engine for which better performing heads are available, then swapping those heads on may work. The combo would still require a custom intake manifold.