4.8/5.3 engines
 

I've been working on doing my homework here. I blew my rear rotor a few days ago and decided after 10 years and 3 engines that it's time to abandon the rotary.

I think I've decided on the smaller displacement LR4 engine. Seems to me as if the lower compression ratio and shorter stroke would be better for what I have planned. And even if I don't (eventually) do what I have planned, it's still a decently powered engine at around 270-285 HP (with that glorious torque thing that rotaries lack). Believe me, the lower power of the 4.8 is not a deterrent for me.

Anyways, through my research it seems like everyone says the intake won't fit with the FC chassis. My question is: what exactly about the truck intake prevents it from fitting? Also it seems that the truck exhaust manifolds won't fit either. So what are the options for making that work?

Most of the info I found through searches here and reading up at grannysspeedshop.com. All it says is that the intake is too tall and you have to use f-body or corvette exhaust manifolds. Are there other options for the exhaust manifolds? And where does the intake interfere?

I have been through the exact process you are going through right now.

From my experience it will end up costing you the same to transplant a truck engine as it will to just buy a Camaro/Trans Am pullout. The extra cost that evens it out is buying all the car bits to bolt on to the truck engine. You will also be up on power and down nearly 100lbs on weight by grabbing a car pullout.

Truck intake is too tall and will contact the firewall and hood. Truck manifolds hit the frame rails. Truck accessories will stick up through the hood. Truck oil pan will scrape the ground.

I used all F body pieces without issue. Would have saved me a lot of time by just buying an entire pull out instead of piecing everything together the hard way. Eventually I ended up swapping in a aluminum block anyway and the car drives just as easy as it did with the rotary.

Hope this helps, feel free to ask any questions!

If you can get the 4.8/5.3 cheap enough you can make it work for a bit cheaper you just need to have patience and some luck, and be willing to scour LS1tech, craigslist, ebay etc for the parts you need cheaply. If you just want to buy something and have it be correct, concentrate on getting a Fbody or GTO pullout.

You will need the Fbody oil pan for sure, a LS1 intake and Fbody or Corvette accessories. Then you will need a flywheel, clutch and T56 transmission if you go manual trans.

I bought an Fbody pullout with a spun rod bearing with an automatic, rebuilt the engine and switched it to manual transmission.

I've been looking for a while, and I'm losing patience now :D

I figured it had something to do with the firewall. If it were just the hood, I assume people would have just said to use a cowl induction hood. And I also concluded it was as expensive as just straight buying an ls1 pullout. Searching around it seems as if the ls1/T56 pullouts go for about 5k and up (emphasis on the up). Rebuilding the rotary that I had (which made close to 350whp) is about 2k if done properly. So looking at this from the perspective of a man who has a wife/kids and not a lot left after paying for dance lessons, the v8 swap is probably not for me.

However, I have my eye on doing a much less costly swap. Considering that I have decent fabrication skills, this one doesn't seem as if it has to go much past the cost of the pullout I chose. And the torque and HP numbers that can be put out of this engine are looking pretty good, as well as the gas mileage to boot.

I really appreciate you guys for taking the time to thoroughly and thoughtfully answer my questions. It really helped me make an educated decision on which way to go with my car.

if you(or I) can make new intake and exhuast manifolds, then the 5.3 works with a t56?

custom itbs?

If you take your time and slowly acquire parts it can ease the cost. I spent a year and a half collecting parts before bolting mine together.

I originally started with a 4.8 but changed directions for a 6.0. The 4.8s seem to go in the $400 range and I picked up a 05' LQ4(6.0) for $900(only $500 more and same weight with more power) and then sold the 4.8. I spent $2000 for T56 and all goodies to bolt it up. I ran this way for about 5400 miles over the summer averaging 26mpg.

Oil pan setup ran about $200 for everything, accessories I got a deal for around $150 by grabbing individual parts as they came up for sale locally, intake I got an LS2 with rail and injectors for around $300, harness and ecu I got a standalone 98 for $350 and spent $75 at LT1Swap.com for a standalone tune for the parts I ran.

At the end of the summer I decided to swap in an Aluminum block(No power steering) to cut weight and found a 90k LM4(Aluminum 5.3 that can be bored to a 5.7) from a 2004 Trailblazer for $650 fully dressed. If I could do it again I would either start with a pullout, or a L33 if you can get a decent price on one, or the lesser known LM4 which can be had for cheap and are plentiful.

After swapping to the aluminum engine I hardly notice there is no power steering. It drives the same as it did with the rotary.

You should be able to find a nice T56/LS1 pullout for $4k.

Gc3 on NoRotors is running the truck intake manifold, with a cowl hood.

Mistah agreen,

Truck intake/accesories will hit the hood, nothing else. That is the only issue.

With that being said , welcome to the darkside.

I'm still undecided about it now. The parts assets totaled out to a lot more than I expected. So a v8 could still be a viable option. The engine I was looking at is the RB20 or 25. I'm seeing mixed reviews about the pros and cons of each of the rb engines and it kind of worries me a little. Not sure still, but the f-body pullout is looking better as I await parts sales.

You will not regret going LS. There are a lot of options once you get that engine in there to make quite a bit of power, keep decent economy and still have the ability to hop in and drive anywhere without worry. It really is win/win on all fronts.

Hey ruler mark! I remember meeting you at one of the meets in jax once. You may remember my ghetto vmounted convertible.

The more I think about it, the more I'm thinking this may be the way to go. Although a lot of engines have solid reliability, too. I really never questioned whether the Rx7 would start, but I definitely didn't expect it to end without warning like that. Literally just cruising down the road at 60 mph with cruise on and it started shaking really hard. I would imagine an rb20 engine would have no issue with reliability or fuel mileage (2.0 liter, after all) and from what I can see it can make some decent power with good torque, as should be expected from an inline 6. I don't know, I'm still on the fence. The main reason I was looking to go with a 4.8 was for the lower compression and shorter stroke/higher redline so that I could turbocharger it. Engine management would be via another megasquirt, so nothing really hard. But the RB is already set up for a turbo, so I'll just have to wait and see what the part out brings in, as well as read up as much as I can to properly weigh the pros and con's of each.

One thing's for sure; I'm not going to go back down that long, painful, money-bleeding path of trying to reliably and economically squeeze power from the rotary. It's just not worth it now... and I have been a LONG time fan of the rotary engine.

4.8L, ls9 headgaskets(100$), china head studs, china gt45r, 25#, no intercooler, and 2200ccs of meth. boom.

Boom.... yes boom sounds about right.

we did one lasted a whole year then the owner went 5.3l compression tested ok and sold it to someone else whos going to boost it more.

Just wondering here, nothing serious. I can weld, so modifying things is not out of my reach. The only thing I can't do is aluminum welding, I don't have the setup for that. So how bad does the intake hit the firewall? Is it just the seam lip? Could I cut the lip off and weld the seam shut for firewall clearance and put a honkin cowl hood on?

And the exhaust manifolds. How far out do those sit? Could the "frame rails" be modified enough, or is it so much to question structural rigidity at that point?

I understand the oil pan will have to be f-body or I'll have to find a welder to make the truck pan work, so I get that I can't get around that one. My car is low enough, so oil pan scraping is not something I need to deal with.

Mark, I saw your build thread. It's come a long way from when I saw it last. I'm considering using the 4L60E transmission instead of the t56 for the same reason. Seems like you can get a good one for a low price (or a truck engine / trans pullout for less than an ls1). And later down the line when I'm ready to make some good power I can build that transmission to hold a lot more than the T56.

Now that I'm thinking about it, anyone got any firewall to intake manifold clearance pics with their LS engine (on an FC) for reference? I'd like to see if it sits in the trans tunnel too far to make using the truck intake impossible.

Not trying to cheap out here, I'd just like to see my options. If there is a less expensive option that involves more labor, I'd rather go that route. Could potentially save a couple g's to be used wisely in other areas.

I was once in your shoes, looking for the cheapest route. I will admit that I was not willing to bend on having a T56 so that did increase my costs by well over 1k. But in the end piecing it all together ended up saving me very little money, but did cost me a lot of time.

I tried fitting the truck exhaust manifolds and it just was not feasible. Not worth it when LS1 manifolds are ~$80.

The truck intake manifold I can understand, you will be out a couple hundred switching to the car setup. If you are intent on going with a truck engine to curb costs, please consider an LM4, they are just as cheap as the iron alternative, only aluminum and can be bored to ls1 specs down the road. 04-05 Rainiers and Trailblazers had them and most yards to not see them as valuable so you can get a great price for low mileage.

Here is a picture from during my build that will show the firewall to intake clearance with an LS2 intake. You can probably get away with trimming the lip that sits back there, I never really gave thought to the truck manifold because I wanted it all under the hood.

Attachment 633613



Here is a picture of where the intake lies with the hood line. It barely clears, but does.

Attachment 633614



In this picture if you look closely you can see how close the LS1 manifold is to the frame rail.

Attachment 633615

I'm finding out now that I like you v8 guys more than the rotary guys.

I've been looking for an aluminum variant of the 5300 or 6.0L, but I'm not getting much around here. There's still time. I'm not going to be rushing this. I really don't want it to look like shit, or worse run like shit!

How about header flanges? Anybody got a good source for that if I want to do some fabrication?

Not sure on header flanges. I am sure someone will chime in with a good source.

I checked around local salvage yards and asked them what they had for 04-05 Trailblazers and Rainiers. I found 4 in a nearby yard that ended up having the LM4 and got one with under 100k for $650 fully dressed including harness and ecm with a 60 day warrantee. After talking to the guy for a while I discovered they jack up the prices on the L33 quite a bit but had no idea about the LM4.

So I went to my local LKQ today and got pretty disappointed. No gen III small blocks at all. Lots of TBI 350s (do not want) and they had at least 4 trailblazers with the LL8 4.2 I6. I looked at it for a bit. They seem somewhat compact, but I'm not sure on the height. Decided that trying to find out wasn't worth it and moved on. Man, I sure wish your junkyards were here. I would have snagged one of those with the transmission and been on my merry way!

Next thought:
Does anyone know which exhaust manifolds fit in the FC engine bay if you flip them upside down such that the outlets point up and forward? I will be throwing a single turbo on, so I'll be utilizing the space in front of the engine for that. I read up about flipping the manifolds on ls1tech, but many of them had fitment concerns based on either hitting coils or the frame. I guess I could figure it out when I get one, but I'm still in the "figuring out" phase I guess.

A lot of guys run flipped truck manifolds. I know of a local guy who used one truck manifold and one car manifold for more clearance. Another local guy used truck manifolds, only cut the flange off and welded on v bands to help clear things.

Limequat's 4.2l I6 Swap

This is somewhat interesting. This guy put an LL8 in his supra with minimal clearance issues. It does have a front sump, but that engine came all aluminum and had 290hp. It mates to a hummer H3 manual transmission, but you have to figure out how to adapt the flywheel. It's a 5 bolt flywheel with a 6 bolt crankshaft. I wonder how much different the fc bay is from the supra... if all else fails and I can't find the right gen 3 small block.

That would be an interesting swap! Probably get those engines cheap I would imagine.

The engine is irrelevant at LKQ. All fuel injected engines are $275, or $350 if they pull it. All transmissions are $125, $155 if they pull it. The biggest issue I had with their lot is that they had all the hoods propped open on all cars, and people just start picking them clean without regard to the next guy. So many of them had valve covers off with rusted cams or heads removed with rusty cylinders. It's like nobody cares at all. The only ones that were any good were the trailblazers, which were mostly untouched and they were also the only ones with the hoods closed. Makes it somewhat desirable. I'll look in to it more, but I still want a small block.

OK, so I went to lkq on new years day. They had a 50% off sale that day. Had to go in to work at 3:30 that day, so I knew I wouldn't have had time to pull it myself. So I go out in the yard and enthusiastically search for my donor. Within a minute I located the engine I wanted. 06 trailblazer with the LL8 engine. It was complete minus the alternator, but another one that was sitting close by had one. So I talked to the guy at the counter and he pointed me in the direction of 2 guys standing outside. "Go talk to them if you want it pulled". OK, so off I go. They look at it and I tell them I want the engine, ecu, wiring harness, and everything that it'll need to run in another car. They were surprisingly taken back by that " odd" request, but they finally agreed and said $300. Hmm... OK, so they want $300?! Even less than listed. "Sweet, so i just go pay up front?", I said. " No, you pay us". "Wait, so I just pay you guys and that's it?" "No, you pay us, we'll pull the motor. We don't work for them. Whether you leave it here or pay them and take it is up to you". (Mind you, they sound more intelligent in my recollection than in real life... they were retards) So that's when it sank in. These knuckleheads are freelance mechanics working the yard. So I stroll back up and talk to the guy at the counter. I asked them why the guy wanted to charge me $300 to pull a freakin engine when their website says it's $350 pulled. He comes out to look at it and says it's going to be $400 for everything I want, but lkq doesn't pull parts. " But I can show you on your website that it says $350 pulled!" The guy kind of stammered a little and goes inside with me to a computer and shows me a different web page than what I saw. "See, there's no price 'pulled', just a price for it, its core, and an extended warranty if you want". Two words is all I spoke (can you guess which two? I'll give you a hint, it wasn't 'no thanks') I go back home and look at the site. Yep, I was right. How could they have something different?! I go back to he site a few hours later... and it's changed to what they had in their office. Hmmm. Seems shady.

So whatever. The search is back on for a 4.8 or 5.3.

So now, let's talk transmissions. I want a manual, but damn is the T56 expensive. Can't see myself justifying over a grand (minimum) for a transmission, especially when they all have pretty high miles. So I thought about doing an automatic like a 4L60e or 700R4, but I can't bring myself to make my " fun" car an automatic atrocity. It would hold the torque better, but still... you know. Can't really have the same fun with an auto. Anyways, I start looking in to an alternative and I come across the T5. Now, the internet shits ALL over them. But is it really that bad of an option? I'm not some sideways-hat wearing teen who slams every shift and sidesteps the clutch every gear change. I feel pretty respectable when it comes to caring for my cars, and I only romp on the throttle on occasion, but only for the duration of a gear, then a nice, smooth shift, easy transition, followed by another romp if the speed limit allows. From what I found, the WC T5 is found in all gen3/4 camaros (different input shaft splines) and mustangs. The mustang GT T5s were built to handle around 300-330 lb-ft, which is in range of the 5.3. So how viable is that option? I've done a lot of searching and found minimal info on putting one behind a gen4 small block. Seems like people run in to issues with the slave cylinder and TOB. Anyone have a more definitive answer?

A T5 will run ok behind a 4.8 or 5.3.

Yes you will have to come up with a slave cylinder and TOB setup, but I don't have a definitive answer for you on what works and what does not.