New Member (1986 Monte Carlo SS) Father/ Son Project

[Mackin_1992]

Hello Everyone,

I am new to this forum and was looking to introduce myself as well as network with some subject matter experts here. I have purchased a 1986 Monte Carlo SS as a roller and am looking forward to going through the car with my father as well as some friends. The G Body Monte Carlo's are sentimental to me as my father had a 1988 Monte Carlo SS when I was a kid.

The roller car I purchased came with some pretty nice parts for a BBC set up (Hooker Super Comp Long Tube Headers and a TH400 Cross-member). I am hoping to get some opinions from members here as far as recommendations for an engine and powertrain combo for my Monte Carlo. My father when I was a kid had a BBC 454 in his, however my friend's at work are all encouraging me to swap an LS motor into the car instead of a BBC.

I have researched the pros and cons of each swap and it appears that the LS engines are promoted primarily because of their reliability, price and availability, however there are a lot more mods that are needed to get an LS installed into a G Body. If I were to swap an LS motor in the Monte Carlo I would want to keep the fuel injection because to go through all the work of swapping an LS motor into the car, just to put a carb on it seems pointless to me unless I am missing something. According to my research the easiest/ cheapest route would be to get an entire pull out from a wrecked truck or car and utilize a stock ECM and stock wiring harness to get it running.

That being said after doing some research on LS engines it appears that generally speaking the LS engines need to be rev'd to reach their power bands, whereas their big block counter parts have more power without needing to hit 5K RPM. If I was to swap in an LS motor I have been looking at a 6.0L LQ4 as a base, but my concerns are that because of the lack of "cubies" present in the 6.0L vs the BBC 454 I will disappointed in it's low end raw power. I also want to keep the engine naturally aspirated and not super charge or turbo it, which is kind of making me think I will disappointed with an LS and should stick with a BBC.

My primary purpose for the car will be street driving on the weekends, but I want to have the car to have that raw power feel of "putting me in the seat" that my dads BBC had when I was a kid. I am looking for more torque than HP as this car will see minimal strip use if any and I want it to have a power in the lower RPMS as that is where the engine will be while "cruising".

I know that there have been forums addressing the LS vs BBC here in the past, but I am looking to gather opinions based on my unique application and intended use. Any opinions are greatly appreciated and I look forward to hearing from you all. I would request that opinions be accompanied with an explanation or links to information to support your opinion. Thanks in advance for your time and I look forward to meeting everyone.

 

[el camino ss 84]

Big block would be the easiest and wouldn't need as much work or money compared to 6.0 lq4. yeah lsx efi motors are reliable but require alot of attention till everything is fine tuned and all the bugs worked out especially since they weren't in gbodys originally.

 

[Mackin_1992]

El Camino SS 84 thanks for the response!

The BBC is definitely enticing as even a mild build has GOBS of low end torque and will put you right in the seat without as many mods as the 6.0L LSX engine would require to do the same. I know it's not quite a "fair fight" as we are comparing a much larger motor to a much smaller motor, but I am just trying to get an idea as to what direction I want to go with it. My gut is telling me to go with the BBC as I know I can make the amount of raw power that will make me smile when I drive it.

 

[565bbchevy]

It seems to me the BBC carries all of the sentimental value here and besides it will easily meet your power goals and the feel and sound of raw power plus the added benefit of already being set up for it makes it an easy choice for me but I am also a little biased.

 

[565bbchevy]

If you do decide to go with the BBC make sure you run a roller cam it's worth the extra money for easy break in and from a reliability standpoint.

 

[Texas82GP]

The LS swap is great. My brother and I put a 6.0/T56 Magnum in his 78 Z28. It's a beast but it's not a torque machine like a BBC. It wants to be revved. The LS swap can be very expensive depending on what you want. Yes, you can buy a truck engine and reuse everything to go the budget route but in my opinion, what you have in the end is a truck engine in your car that doesn't fit the chassis very well. The truck intake is ugly and is too tall. The truck alternator is way too close to the bottom of the hood. The truck power steering pump is too close to the power steering gearbox. The truck oil pan hangs way too low. These are all just my opinions. You can make all that truck stuff work but it is just too many compromises to keep the budget under control for me.

We used a 6.0 (L96) in my brother's car. We stripped it back to a long block. We bought custom mounts and headers. We ditched the VVT. We changed the cam and valve springs. We swapped to the F-body oil pan and to an LS3 timing cover. We used an LS3 intake and a Corvette front accessory drive. We used a Holley drive-by-cable throttle body, which necessitated using a GEN III computer and the Lingenfelter 24X to 58X conversion box. It would have been easier to use a drive by wire throttle body and gas pedal but that wasn't the feel that we wanted from the car and we already had a GEN IV motor.

In the end it turned out fantastic but it was expensive. We wanted it to look like it would if GM had put the engine in the car and I think we succeeded. In the end you just have to be real honest with yourself regarding what you want to spend and what you want from the car (look, feel, performance).

It sounds to me like the BBC is the way to go on your project but only you can decide that. Depending on what you will do with the car I would give serious consideration to an overdrive transmission (T56 Magnum or 4L80E).

Here is a pic of my brother's engine compartment. Food for thought.

 

[Mackin_1992]

565BBChevy Thanks for the input.

The BBC definitely is a sentimental aspect of the car for sure. They sound completely different than LS engines do and give that raw ground shaking power. I am definitely wanting to go with a full roller set up as my dad did a flat tappet set up and one of the tappets twisted and trashed the engine...

All of my friends at work are younger like I am and are LS fanatics, which there is nothing wrong with LS engines, but even when they are built they seem to need to "scream" to make any power. I know it will be easier to go with a more mild build on BBC to get the power I am after, but they tell me horror stories of all the carb problems associated with old school engines and how they require constant adjustment and maintenance. I don't remember my dad having problems with a carb stalling out ever, just the engine liked to overheat sometimes and cold starts could be hard.

Everyone has an opinion and I am just looking to confirm which route I want to take. I am leaning towards BBC because I can spend more money on parts because it won't require all the specialized swap parts to get it to work in the car. I also have the Hooker Super Comp Headers and the transmission cross-member for this set up as already which is a $1000 start in the right direction. I don't want to make the mistake of building a car around the fact that I have a few parts laying around for it though either.

 

[Mackin_1992]

Texas82GP Thanks for your input!

I am definitely leaning towards a BBC personally, but my friends are telling me that the LS engines are cheaper to get the same power from. After researching them both honestly, by the time you take into consideration all of the specialized components and modifications required to get the engine to work in the older chassis application I think they are wrong.

I would really like to get a modern transmission behind a BBC if I went that route, but I am not sure of the compatibility issues I would run into trying to get a 4L80E to bolt up to a BBC? Do you know where I might be able to find any information pertaining to which generation BBC are compatible to having a 4L80E bolt up or what modifications are required to do so?

I do like the set up that you have in the engine bay with the LS swap you did, but to me it just does not have the same WOW factor under the hood that a dressed BBC does. It is definitely a matter of personal preference though and I honestly enjoy seeing everyone's different set ups and appreciate them.

 

[Texas82GP]

I'm no BBC expert but I'm certain it won't be hard to put a 4L80 behind one in one of these cars. There are several knowledgeable guys on here that run BBC power so hopefully they can help.

I'm proud of the work we did on my brother's car but I agree with you that a BBC is more handsome. The LS engines are kinda homely in my opinion. I think the truck stuff is even more homely. I don't really think it looks that great under the hood of my 08 Sierra.

It's all in what you want. My brother wanted a fuel injected LS so that's what we did. When I got my car I had a bare 6.0 block available but I've done an LS swap and I want to build the car I wanted in the 90's so I'm going with a 350hp 350 with a serpentine accessory drive, a quadrajet, long headers, A/C and a T5. I want a spunky cruiser and I want the more old school aspect of the carb. I already have a fuel injected LS in my dailey. Also the SBC is more in my budget because I wouldn't settle for using the truck stuff.

 

[Mackin_1992]

Texas82GP

I am sure I will run into those that are BBC experts in due time, on the bright side I am no where near that point yet anyhow. At this point I am more interested in just gathering and learning as much information as I can so that when I am at the point in the restoration I can make the best informed decision I can as to which route I want to pursue.

I definitely want to mindful of the fact that this car will primarily be a street car and build it accordingly. I don't want to have it fight me when it needs to sit and idle at a traffic light. I agree with you in the idea that it is nice to have the classic aspect of a carb in a classic car instead of just fuel injecting, which results in looking and performing like most vehicles on the road.