Hooker 73-87 GM truck LS swap system

[toddoky]

Hey folks. I just signed up here as a user last week for two specific reasons, one of which is to support my own squarebody addiction (I've owned 3 and currently am working on a 79 C20 project)and the other is to build a thread to provide information about the new Hooker LS swap system of components for these same trucks. I want tell you up front that I'm the design engineer at Holley who's responsible for developing all of the Hooker LS swap components, which will explain why I will only be sharing technical, operational, compatibility and fitment information here...I'm not very good at selling things, so I stay clear of that segment of the business.

I've been sharing the same information and pics you'll see me post here on another popular LS enthusiast website for quite a few months regarding this set-up and noticed that it was not trickling over here for the collective benefit of the members here, so I did some prodding within Holley management and convinced them sign-up as a sponsor here so that I could have the freedom to share information freely with anyone who is interested in reading or asking about it.

I think that's a good start to the introduction, so let me get the meat and potatoes listed for you that will give the basis for formatting questions and comments that you may want shared with other members here.

The direction behind the design of this Hooker LS swap system of parts was the same as it has been for all of the Hooker LS swap systems that have come out over the last 3 years, which is to say that every component is designed with the knowledge of how in would affect the fitment and function of every other part in the system.

An example of this would be the necessity of the transmission crossmember to have the highest exhaust passage clearance available in order for the headers and exhaust systems to be able to provide the best available off the shelf ground clearance under the truck.

I'm feel I'm getting a little too wordy, so here's what's available and some overall photos that show the components installed:


1. Specific factory clamshell style engine mounting bracket kit.
2. 1-3/4" and 1-7/8" long tube headers- in mild steel and stainless steel
3. Cast iron LS exhaust manifolds with available exhaust system adapters
4. Transmission crossmember compatible for installation of a 4l60-4L70,TH400 ,2004R, 4L80-4L85, T56 or T56 Magnum transmission in your truck
5. 2.5" and 3" stainless steel exhaust systems with rear exit or side exit tips

Remember that all the above components are bolt-in installable with one another in your driveway.
And the photos to come...
[IMG][/IMG][IMG][/IMG][IMG][/IMG][IMG][/IMG][IMG][/IMG][IMG][/IMG][IMG][/IMG]

[BR3W CITY]

At least your up front about working for them. I don't mind reps as long as we know where the confirmation bias comes from

Anyway, I know the headers are an issue that gets a ton of attention around here. If you can help confirm deny their fitment on other years I know it would help us a ton. I'm in a 66, but with a 72 crossmember/suspension. Some here have used the 73+ stuff to great result, others say there are clearance issues. If you have input on that, I'd appreciate it personally.

[toddoky]

Originally Posted by BR3W CITY

At least your up front about working for them. I don't mind reps as long as we know where the confirmation bias comes from

Anyway, I know the headers are an issue that gets a ton of attention around here. If you can help confirm deny their fitment on other years I know it would help us a ton. I'm in a 66, but with a 72 crossmember/suspension. Some here have used the 73+ stuff to great result, others say there are clearance issues. If you have input on that, I'd appreciate it personally.

Thanks for posting. Yeah, I see no reason to hide my employment with Holley and have found that by disclosing that fact up front that it helps me to develop a good report with other users and makes any threads I put up a more active source of information for all involved.

As far as fitment confirmation of these headers on any earlier model year of Chevy/GMC truck is concerned, I'm afraid I'm not much help on that one either way as I've not had the opportunity to test fit them on anything other than multiple year squarebody trucks. I feel in time we will get around to developing parts for the earlier trucks, but I don't know when that will be.

[mongocanfly]

Welcome aboard..are those just teaser shots of your truck? How about some whole truck pics..it looks good...I had heard holley was working on headers that required no frame cutting..most of us had to cut the frames on our square trucks.I know a big issue I had was clearing the manual clutch z-bar linkage when looking for headers and wound up with a set designed for a hummer..I still had to mod a bunch to make it work ..my next 2 projects will be the ad chevy trucks so don't forget about us either.

[toddoky]

Originally Posted by mongocanfly

Welcome aboard..are those just teaser shots of your truck? How about some whole truck pics..it looks good...I had heard holley was working on headers that required no frame cutting..most of us had to cut the frames on our square trucks.I know a big issue I had was clearing the manual clutch z-bar linkage when looking for headers and wound up with a set designed for a hummer..I still had to mod a bunch to make it work ..my next 2 projects will be the ad chevy trucks so don't forget about us either.

Thanks for the welcome, truly. The headers and exhaust system shown together in the bottom-up shot are prototype parts that were built at the end of last year, but the engine brackets, crossmember and the stainless headers shown in the under-hood shots are all off the shelf production parts. Everything is now available, so I will get around to taking some new photos of the exhaust in the near future. As long as you use the Hooker engine brackets and crossmember to mount your powertrain, there is nowhere that the clearance becomes tight with the headers. This is speaking only in terms of 2WD applications, since these parts are not 4WD compatible. There was no attempt made to make these headers compatible for use with a Z-bar/mechanical linkage set-up, so it's doubtful that by luck they would be. The truck shown belongs to an engineering lab tech who works for Holley and there are four others of us who work on the Hooker development team who own squarebodies also.

[Hart_Rod]

Thanks for posting! How about some prices, .

[toddoky]

Originally Posted by Hart_Rod

Thanks for posting! How about some prices, .

Pricing will depend on where you buy the parts from, so there is no black/white answer to that popular question. The C10 truck LS swap application is highlighted on the home page of the Holley website currently, so it's real easy to browse through all the available parts and get part numbers that you can use to check pricing from various sources.

[toddoky]

For those of you who like to read or crave more info, here's a PDF that covers the technical and compatibility characteristics of the components...

[rs74]

How does the factory LS A/C compressor work with all of this? Can it be retained in its factory location without cutting the frame if the Holley clamshells are used?

[toddoky]

Originally Posted by rs74

How does the factory LS A/C compressor work with all of this? Can it be retained in its factory location without cutting the frame if the Holley clamshells are used?

The engine brackets are compatible with the later factory truck compressor that does not have the rear sensor on it, but the edge of the front lip of the clamshell mounting brace on the truck will need to be trimmed slightly to clear the compressor.

[Misled]

toddoky,
Are you allowed to say whether buying from Holley.com is better or worse than a vendor?

Thanks,

Misled

[toddoky]

Originally Posted by Misled

toddoky,
Are you allowed to say whether buying from Holley.com is better or worse than a vendor?

Thanks,

Misled

Sure, the ability to purchase from the Holley website was developed to provide convenience to visitors of the site. That said, it's rare for you to find the pricing to be your lowest available option. Purchasing from a Holley reseller also provides other advantages, such as special package discounts that we don't offer and the ability to one-stop shop for other non Holley products.

[Misled]

Originally Posted by toddoky

Sure, the ability to purchase from the Holley website was developed to provide convenience to visitors of the site. That said, it's rare for you to find the pricing to be your lowest available option. Purchasing from a Holley reseller also provides other advantages, such as special package discounts that we don't offer and the ability to one-stop shop for other non Holley products.

Great, thanks!!

Regarding the oil pans.....which would be better for a 1978 C10 with an LS1 and 4L60E? It will be lowered 3/4 or 4/5.

[toddoky]

Originally Posted by Misled

Great, thanks!!

Regarding the oil pans.....which would be better for a 1978 C10 with an LS1 and 4L60E? It will be lowered 3/4 or 4/5.

Both the 302-1 and 302-2 Holley pans will install with the Hooker system of parts on your truck with the bottom of their sumps remaining above the bottom of the engine crossmember. The 302-2 has a typically lower price, so that may sway your opinion in determining which is best for you. The only advantage I give to the 302-1 is its ability to accommodate crank strokes beyond the common 3.62"

[toddoky]

Originally Posted by Misled

Great, thanks!!

Regarding the oil pans.....which would be better for a 1978 C10 with an LS1 and 4L60E? It will be lowered 3/4 or 4/5.

Both the 302-1 and 302-2 Holley pans will install with the Hooker system of parts on your truck with the bottom of their sumps remaining above the bottom of the engine crossmembmer. The 302-2 has a typically lower price, so that may sway your opinion in determining which is best for you. The only advantage I give to the 302-1 is its ability to accommodate crank strokes beyond the common 3.62"

[crazy longhorn]

I have been a backyard "fab man", for many yrs, & pretty good at it. I do not build my headers, so I am left to what fits? The total package, looks like a really slick deal....man it all fits nice! For the guys that don't have the time/experience, the kit looks like a bolt in deal From what I see, all of the parts work as a kit.....you don't get that, from parts from this ,or that manufacture! Nice job, to the Holley guys! As far as the ? on the headers fitting the mechanical clutch linkage on that square body truck....have the techs check it, but the ball pivot screws into the bell on that truck? If the mounts , set the engine in the stock spot, my bet is that the bell crank will clear the headers? Once again, good work ....Longhorn

[mongocanfly]

Longhorn.. my bellcrank clearance issue was that every set of headers i tried "even though they said they would fit" and the stock manifolds that came on my engine was the outlet/collectors all wound up exiting right where the bellcrank crossed from the frame to the engine.what I found was the hummer ls headers dropped strait down between the 3rd and 4th cylinder on drivers side and then turned back..but I still had to work on header mod and frame mod ..if they made a header for our square trucks that would clear a bellcrank it would also work on any square truck..I do realize a manual clutch is not what most people do though..

[toddoky]

Originally Posted by crazy longhorn

I have been a backyard "fab man", for many yrs, & pretty good at it. I do not build my headers, so I am left to what fits? The total package, looks like a really slick deal....man it all fits nice! For the guys that don't have the time/experience, the kit looks like a bolt in deal From what I see, all of the parts work as a kit.....you don't get that, from parts from this ,or that manufacture! Nice job, to the Holley guys! As far as the ? on the headers fitting the mechanical clutch linkage on that square body truck....have the techs check it, but the ball pivot screws into the bell on that truck? If the mounts , set the engine in the stock spot, my bet is that the bell crank will clear the headers? Once again, good work ....Longhorn

Thanks for posting crazy longhorn and for the compliment on the job being well done. I'm glad to see you noticed the full-system approach to the components; quite a few users miss that point since this swap application has been done by the mixed-bag method for so long now.

Compatibility of the headers with the stock mechanical clutch linkage is something we normally leave on the table with our swap systems as it represents too small a percentage of users to justify the increase in build and installation complexity required to make it happen. By allowing ourselves to use the space occupied by the linkage in the design of the headers we are able to produce a lower cost, better fitting and easier installing set of headers for the majority of swappers.

[rs74]

Question. Are the middle of the mounting flanges on the hooker exhaust manifold supposed to be split or one piece. I see in one of the pics you posted above they are one piece but then I saw these.

[toddoky]

Originally Posted by rs74

Question. Are the middle of the mounting flanges on the hooker exhaust manifold supposed to be split or one piece. I see in one of the pics you posted above they are one piece but then I saw these.

The cast iron manifolds are split to allow for expansion, the pictures I posted all show header flanges, which are not split.

[rs74]

Originally Posted by toddoky

The cast iron manifolds are split to allow for expansion, the pictures I posted all show header flanges, which are not split.

Ha! Yep, I guess I should have looked just a little closer there.

[Advanced Design]

I really do like the system application with these parts. It saves a ton of research and fabrication time plus eliminates the frustration of having parts that don't fit...not to mention cost. Nice job toddoky!

Can you post more pictures of the red truck? Looks really nice.

[toddoky]

Originally Posted by Advanced Design

I really do like the system application with these parts. It saves a ton of research and fabrication time plus eliminates the frustration of having parts that don't fit...not to mention cost. Nice job toddoky!

Can you post more pictures of the red truck? Looks really nice.

Thanks for noticing the effort behind the design, we really did set out to remove a lot of headaches from this swap. More pictures, sure...[IMG][/IMG][IMG][/IMG][IMG][/IMG][IMG][/IMG][IMG][/IMG]

[mongocanfly]

Good looking square...

[Advanced Design]

Beautiful truck! Thank you. A bit off topic...I see two fuel tanks and was wondering what he used for a pump? Guessing one external Holley plumbed to both tanks?