BritishV8 Forum

Scott, I have a 74-1/2 MGB out in the shed. We put a V6-60 in it. I am pretty familiar with the differences thank you very much. My comments stand. You'll have to prove it before I will ever believe it. Every LS conversion I have ever seen had radical cuts to the firewall, yours is no different, and the RB firewall doesn't give you any more room where you made those cuts.

If you will recall, I tried to persuade you to try to do your installation without doing firewall butchery but you wouldn't listen to me because you had other ideas. So don't try telling me now that I am wrong.

Jim

Jim is from Missouri.  

Scott put that engine exactly where he wanted it.  Other locations would be interesting.

As for a kit, I have been hearing that rumor for a long time. May not be too long, now.  

QuoteNot clear if you can do that to an LS1.

Carl, if you're wondering about using a 148 tooth flywheel I suspect the answer is yes it can be done. If you're going to go that route and 5.3l will do the job for you you might as well go with an LS4 at that point mainly for the costs.

QuoteScott, I have a 74-1/2 MGB out in the shed. We put a V6-60 in it. I am pretty familiar with the differences thank you very much. My comments stand. You'll have to prove it before I will ever believe it. Every LS conversion I have ever seen had radical cuts to the firewall, yours is no different, and the RB firewall doesn't give you any more room where you made those cuts.

If you will recall, I tried to persuade you to try to do your installation without doing firewall butchery but you wouldn't listen to me because you had other ideas. So don't try telling me now that I am wrong.

Jim, I was trying to make a point and now that I reread it it sounds like I'm trying to be condescending.....not my intent. I still disagree with you though. ☺ In this case I suspect my idea of minimal mods will always be radical mods in your eyes.

What I see and what I have been told is the rack on a RBB is 1" further forward when compared to a CBB. Also the curvature of the hood is greater on a RBB. You will be able to move the engine forward an inch and mount it higher in the engine bay because of this. That will make a huge difference. Given the steering is mounted  lower in a RBB I'm confident the steering will stay put judging by how the LS4 fits into my CBB. You will have to make allowances for the heads by the firewall. In any event I can't see how you could describe the modifications as "radical". We will see.

As Carl stated, the engine is exactly where I want it. I spent over two years planning the conversion so I didn't just randomly decide to place it there. I'm trying to make a point again and I know you know this but no matter where you place the motor you will be making a compromise. More rearward you're looking at firewall mods, more forward involves the steering rack and radiator placement. Pick your poison. For me it was never a question that I was going rearward. Oh, just for the record, "weight distribution" wasn't even a consideration in my decision.

Any plans to go to the Dayton show this year? I think it's on the 6th of August. Hope so. I'm pretty sure I'll be there for at least part of the day.

Scott

QuoteIn this case I suspect my idea of minimal mods will always be radical mods in your eyes.

Now, that is hysterical.  

I agree with Jim, though, the closer the LSwap can be made to a bolt-in the more popular it will be.  Personally, I am not chasing 300+ HP, so there is no sheet metal surgery in my future. This is why the 3.4 V6 is so popular.  The power hungry junkies have no qualms about cutting it up to get their fix.    That is why Pete has sold 65 Ford V8 kits. Wow.

Thanks Scott, to be fair I had let myself get a little irritated. Not my finest moment.

I would indeed like to see a "bolt-in" LS swap. If that could be done it would be a fine thing for the MGB conversions.

Regrettably, I suspect the RB advantages of rack placement and hood curvature may not be as beneficial as you hope, but that's no reason not to try. Realistically however, given what we are working with the only way to do it is to, well, actually do it.

Jim

I forgot to address the bonnet. IMO, that the RBB bonnet has more curvature than a CBB is a urban myth.

If I were to entertain an LS variant, I know it's not the cubic inch thing to do, but I have a fixation on using the 4.8L short stroke crank. Something like a 4.00" bore with a 3.267" stroke.  

That should make an engine that would suit you well Carl, at least I would think so. If it was LS4 based with Scott's flywheel and starter setup it could have a decent chance, but depending on engine location I wonder just how great that an advantage the smaller bellhousing really is. To fully take advantage of the forward position some crossmember bashing to lower the engine a bit might be helpful provided the rack can be cleared.

I'm very familiar with forward engine placements. My engine, and probably the 455 are located farther forward than any other conversion I've ever seen. Typically with the Buick the rack/pan interference is the limiting factor if the engine is positioned forward of the usual location with the rack between the damper and the front cover. The rack can be lowered but this can bring further complications beyond a limited point. With the crank pulley of the LS4 being tucked in tight to the cover the same conditions apply to pulley/rack clearance. Moving the accessory drive out away from the front cover could allow the engine to be lowered by straddling the rack if the parts are available to do it. (could require balancing) It could also allow the engine to be moved further forward at which point pan to crossmember clearance becomes an issue.

Like I say, I'd like to see it done. In fact Carl, if you come up with an engine I expect we could test fit it in the Chump car to get an idea of what you'd have to do to put it in yours.

Jim

How about a plastic block w/bellhousing?

Wouldn't hurt to compare the SBC & BBC bellhousings to each other. It would likely be cheaper/easier to use the stock 14" flywheel & BBC bell.  I think I have a spare bell, not sure which one.

Fitment check.  It fits, sort of.  I want to raise the tranny tunnel and clearance the firewall.  That tube at the rear of the engine bay is in the way by about an inch.  I'll cut that out and move it back.  Tomorrow I will try and find the time to cut out the spine of this beast and start bending some new panels.  I wanted  to raise it and widen it TVR style.  That should give extra room to run a 3" exhaust if I so choose.  The Camaro headers don't fit.  They hang way too low.  Need to go get a set of shorty headers.  The Camaro has an aluminum hood that is very lightweight.  Laid the TR7 hood over it and its just big enough that I can cut out a TR7 hood from the aluminum Camaro hood.  Has the built in power bulge down the middle to give me a little more clearance over the intake manifold.  I was planning on making a fiberglass hood, but the aluminum is cooler and easier to do, plus its going to be free.

That looks pretty good. I think it will fit.  How does it look on the bottom, with the crossmember?

I think the deep part of this style pan extends a little too far forward to use the stock cross member.  Its similar to those larger aluminum pans on the 4.0s that don't fit with the wedge subframe.  I'm planning on making a tubular cross member anyway, but there are other oil pans that will fit with the stock cross member.  Where I had the engine sitting in the driveway is about ride height, and the body was lowered to about ride height, based on measurements taken from some of the other wedges here.  Todays exercise was just the first fitting.  Time to cut and remake the tunnel, and cut back a couple of bulges in the firewall.  Then check again.  Then make the engine and tranny cradles.  Biggest issues are engine won't go all the way back to the firewall because of roll cage tubing and tranny tunnel is not tall enough to use remote shifter.  Doing away with remote shifter and going straight out of the top of the tranny will place it too far forward, so easiest solution to those issues will be to cut out and remake the whole tunnel.  Enlarging tunnel cutout area in firewall and rear bulkhead will allow the engine to go back another 2.5" comfortably, and will give more room for the exhaust and the fat driveshaft I need to run.  If the engine stays right where it is now, I may have steering rack to oil pan clearance issues.  Get it back a couple of inches and I'm sure there won't be a problem  When the pictures were taken, there was still 3 plus inches between the back of the heads and those bulges in the firewall I want to smooth out.  If you know TR7s, its right where the coil sits and on the other side of the tunnel near the gas pedal mounts.

LS Accessory-Drive Swap Guide

http://www.hotrod.com/how-to/transmission-drivetrain/ccrp-0905-ls-accessory-drive-swap-guide/#photo-17

LS-Series Engine Oil Pan Dimensions

https://www.improvedracing.com/tech/LS-oil-pan-dimensions.php

Ought to fit no problem now.  Surgically removed the tranny tunnel in one piece so my buddy can reuse it in this MGA thats getting a Ford 302.

This show why the GM LS family is so popular. Easy horsepower.

http://www.superchevy.com/how-to/engines-drivetrain/1306-4-8l-vs-5-3l-engine-tech-little-ls-slugfest/

Not to de-rail the conversation but wouldn't those threads be better suited in a stickie or something at the start of the forum?

I don't think Curtis would want a stickie for every engine choice.  This thread is titled LS Engines.  Those links will be easy to find later via the search feature.

QuoteThanks Scott, to be fair I had let myself get a little irritated. Not my finest moment.

I would indeed like to see a "bolt-in" LS swap. If that could be done it would be a fine thing for the MGB conversions.

Regrettably, I suspect the RB advantages of rack placement and hood curvature may not be as beneficial as you hope, but that's no reason not to try. Realistically however, given what we are working with the only way to do it is to, well, actually do it.

Jim,

No issues on my end at all.

I'm a little behind here.....been way too busy lately.

You are right that someone needs to put an LS in a RBB.....I'm really anxious to see that done. I wish I had an opportunity to try it myself.  I am going to stick by my statement though. I'm going to qualify it to using the LS4 . I just went out to the garage and checked again and still feel the same. Here are a couple of pictures that I think show what I'm trying to describe. This one shows the initial cuts I made.

<img width="600" src="http://forum.britishv8.org/file.php?2,file=13598" />

This basically shows the cut outs for the heads. The LS4 just fit between the rack and the firewall but I couldn't tilt it at all. I needed an additional 3/4" at the firewall which resulted in these additional cuts.

 <img width="600" src="http://forum.britishv8.org/file.php?2,file=13984" />

What I'm saying is I think the RBB mods are going to be closer to the first picture. Do you consider the first pic radical?  These are all guesses but I think they are educated guesses. Hope we find out soon!

QuoteI forgot to address the bonnet. IMO, that the RBB bonnet has more curvature than a CBB is a urban myth.

Carl, I'm sure you're right....I might have been getting carried away a bit. &#9786; I still see all these later grills that seem to be made for a bonnet that has more of a curve (I've got one on my car) and I wonder if they are just poorly made or if a change was actually made to the bonnet at some point? In either case you could use an LS1 or LS6 intake and still gain a bunch of room at the throttle body and bonnet. I have at least a 1/2" to 3/4" there with the LS4 intake.

QuoteMoving the accessory drive out away from the front cover could allow the engine to be lowered by straddling the rack if the parts are available to do it. (could require balancing) It could also allow the engine to be moved further forward at which point pan to crossmember clearance becomes an issue.

Jim,

The truck crank pulley is the only pulley that might work but there isn't much room there. Based on what I see with my LS4 it's going to require you to raise the motor at least an inch if not more and you're going to be into the bonnet in a CBB at least. It's only going to get you around an inch further forward anyway.

The Corvette crank pulley gives you 24" from the edge of the pulley to the bellhousing mounting surface. The LS4 is 23.25 in that same dimension. The truck is the longest by far and the F-body is in between.

I got some pictures for you Scott. The upload order sucks, but what you have here is a top view, (1st and last) and then a detail shot showing the shelf down low on each side (and those are in reverse order. Sorry.)
 








This is an unmolested 74-1/2 which has the factory firewall mods for the V8.

Incidentally, on the Roadmaster, to fit the 455 there were cuts made to widen the tunnel for the bellhousing, but the corner of the passenger side shelf was only moved back 1/2" at the top only IIRC for head clearance, the driver's side being unchanged. The steering rack is below the oil pan.

Jim

Thank you Jim! Very interesting. Someone has to try this.

Well, Carl suggested a plastic engine, wonder if he knows where there is one?

Jim

I bet Pete has one.     I have been looking for a used one.  Not interested in paying $425 for a new one

Yeah, you could probably just buy the LS engine.

Jim

You do know there is a 5.3 vortec engine in my ol'  Silverado?