LS & 4L60 Install - Tri Five 1955, 1956 or 1957 Chevy

[NickP]

A while back, it was time to throw the LS into Geoff's 55Vert, yup, he broke down after months of brainwashing, bamboo shoots under thenails and a little waterboarding.
Geoff decided to use a Street and Performance Motor Mountkit for this install; what follows is the basic install following the suppliedsheet. The instruction sheet left alittle to be desired.
Starting with Geoff's frame (again this is a 55 a vert), Ilooked over the parts in the kit. At first blush, solid, well made andseemingly complete.

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The instruction sheet indicates that the spacing should be19" upon completion of the install.
I have several pieces of 1/4"x2" Aluminum bar stock, soI laid out the hole pattern and built a jig. It uses 5/8 bolts to hold the twomain parts and maintain the 19”. Certainly, one could use just about anymaterial stiff enough to maintain the dimension.
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The hole in the motor mount where the rubber doughnut setsis 1 1/4" in diameter. Interestingly, I had just purchased a bag of boltsthat button up a C4 suspension and located within that bag were two washerswith a 5/8" ID and 1 1/4" OD. Perfect fit.
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I assembled the aluminum bar and the mounts with mywashers and bolts, set it in place as it should be and found very little if anydistortion or ill fit. Once located in the center of the chassis, clamped inplace and began to drill the holes, eight in total - 4 ea. @ 25/64"Clearance for 3/8" and 4 @ 21/64" for the 5/16" bolts. I willadd here that the kit does come with all fasteners/washers but I opted forGrade 8 rather than the Grade 5 supplied.
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With the mounts all buttoned up, it was time to get theblock ready. Years ago, I purchased ajunk block for this purpose and it has been an easy solution. I found a pair ofLS1 heads and an old intake manifold, front cover and other items along the wayto be able to determine any issues in fitment. The main plates supplied in thekit are made from 1/2" aluminum, nicely machines with very clearindication of the side they go on. Followed by the steel mount and after bothsides were done, I added the 4L60. Got out the forklift and added an extensionto reach into the chassis. Lowered it in and it fits like a glove, well,almost. The tail housing of the trans does rub on the X-Member but that is aneasy fix. Geoff had obtained an odd but useful looking trans crossmember forit, but it is for some other application. It will either get modified orreplaced.
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All in all, about 8 hours including making the jig. Next,transmission crossmember.

[markm]

Those mounts are the spitting image of the ones CCI sells in their 2.25 foward BBC kit.

[chevynut]

Nick, I think those mounts are made by Chassis Engineering, but I can't even find them on their website. They're the same mounts I suggested to another poster in a different thread. I'm curious how far "forward" they actually place the LS engine measured from the bellhousing face location.

From the bellhousing face to the centerline of the SBC engine mount is 15.95" per a GM drawing I have. What does the LS setup measure from the bellhousing face to the center of those side mounts?

I'm pretty darn sure those are just S&P's SBC side mounts with an LS adapter plate.

[chevynut]

Those mounts are the spitting image of the ones CCI sells in their 2.25 foward BBC kit.

I don't think so. Unless the mounts also mount a SBC 2 1/4" forward. Those are SBC mounts for a 55-57 Chevy. I have a friend who used them to mount a Ramjet 350 with side mounts in his 55. I'm not sure if they're designed to move a SBC forward or not.

A BBC is the same length from the bellhousing face to the center of the side mounts as a SBC.

[NickP]

Nick, I think those mounts are made by Chassis Engineering, but I can't even find them on their website. They're the same mounts I suggested to another poster in a different thread. I'm curious how far "forward" they actually place the LS engine measured from the bellhousing face location.

From the bellhousing face to the centerline of the SBC engine mount is 15.95" per a GM drawing I have. What does the LS setup measure from the bellhousing face to the center of those side mounts?

I'm pretty darn sure those are just S&P's SBC side mounts with an LS adapter plate.

Not certain of the actual manufacturer of the kit I used but it all came from S&P. From the bellhousing to the center of the hole used in the kit that centers the mounts is 14-11/16" +/- 1/32" for a lousy balance on the ladder while measuring.

1422

[chevynut]

Nick, I'm curious what S&P charges for those mounts. Sachse Rod Shop has them in their catalog for $109.95 with the biscuits and they say "engine sits in the same location as original". They are made by Chassis Engineering according to their catalog.

http://www.shop.sachserodshop.com/product.sc?productId=1175&categoryId=-1

[NickP]

I don't recall what Geoff paid for the kit.

[NickP]

http://www.chassisengineeringinc.com/page4.html

[chevynut]

From the bellhousing to the center of the hole used in the kit that centers the mounts is 14-11/16" +/- 1/32" for a lousy balance on the ladder while measuring.

Hmmmm, that means the engine is only 1 1/4" forward from stock (15.95-14.68) if those are the same Chassis Engineering mounts that Sachse sells. Seems to me that might be pretty tight to the firewall. I move the LSs in my C4 conversions 2 1/4" forward, and they fit well.

Do you have a stock 55-57 bellhousing and mounts that you can use to check the actual placement since you have the bellhousing frame horns still on the frame? Don't want to scare you, but you probably need to find out now if there's any problem. Here's an LS engine 2 1/4" forward in my Nomad with the stock frame. That 55 should be the same.

BTW, where is Geoff? Why isn't he here? ;)

[markm]

I am a little tec. challanged so it would not work to paste photo from Ecklers site, but if you go to instructions for their part # 18-271 BBC mounts I think you will see what I mean.

[NickP]

BTW, where is Geoff? Why isn't he here? ;)

DUNNO..............................

[carls 56 (RIP 11/24/2021)]

looks good nick, nice job. used a very similar set from eckler's (#18-02) to use on a 327 in a 55 i had. didn't move the eng at all. in fact, i even left the old ones hooked up (i'll try a pics). 1429

[Rick_L]

The fore/aft location of an LS engine with that setup is dependent on how those aluminum plates are made. Changing the fore/aft location of the LS hole pattern vs. the traditional engine hole pattern can give you a wide variation in the fore/aft engine location. That's both good and bad. You can do just about anything within reason if you're making the plates, but if you're trying to buy some and just bolt them in it's a tough call as to what to buy. But I've never heard that the S&P mounts put the engine in a bad position.

Speedway Motors and Eckler's sell the same Chassis Engineering mounts. They don't have the LSx plates, they are for traditional Chevy engines. The problem with them on traditional engines is that they mount the front of the engine higher than stock, which causes you tunnel clearance and pinion angle problems. There's a guy over at trifive.com that used the mounts, and sourced some different rubber biscuits to make the engine height correct. I don't know how all that works out with an LS, but on the surface it sees it would still apply.

[chevynut]

You're right Rick, those mounts are just made for a traditional SBC and the aluminum adapter plates are what positions the LS engine. Per Nick's measurements, that engine is 1 1/4" forward of "stock".

Here's the article on using those mounts in a '56 from S&P's website.

http://www.hotrodlane.cc/56chevyinstall/ls156installpg2.htm

It's hard to tell how well the engine fits at the firewall, but it must be tighter by 1" than in my pics above because I put that engine 2 1/4" forward using spacers between the stock 55-57 bellhousing mounts and the stock bellhousing frame horns.

Obviously those mounts work. ;)

[Rick_L]

Chevynut, when you are saying that an LS engine is 1-1/4" or whatever from stock, are you talking about the bellhousing mounting surface? Knowing that it's further forward than a traditional engine because they eliminated the "shelf" that's there on a traditional block. That point of reference is confusing for many including me.

[chevynut]

Yes, if you read the posts above I calculated where the bellhousing surface would be relative to the stock SBC location. Those Chassis Engineering mounts apparently put a SBC in the stock location, and I had Nick measure the distance from the bellhousing surface to the center of the SBC mount. The difference was 1 1/4".

The absence of the "shelf" is why you need to move the engine forward so much.

[Bihili]

I am a little tec. challanged so it would not work to paste photo from Ecklers site, but if you go to instructions for their part # 18-271 BBC mounts I think you will see what I mean.

http://www.classicchevy.com/chevy-side-engine-mount-kit-big-block-1955-1957.html

click on PDF

[chevynut]

Those CCI BBC mounts do LOOK the same or very similar to the ones Nick is using. As I said, the SBC and BBC blocks have the side mount holes in the same location from the bellhousing face so using the same mounts will put them in the same location. The BBC is almost 2" longer forward of the mount holes.

So something must be different in those mounts.

[chevynut]

Never mind. :)