1975 Imperial build thread

[commando1]

Does anybody have experience with these things?

Yes and I hear about it a gazillion times.
The starter is not bolting up flush because it's rubbing up against the block and you need to do some grinding.
You also can't use the connector that comes with the mini starter.
AMHIK X3

 

[3175375]

There’s a

Yes and I hear about it a gazillion times.
The starter is not bolting up flush because it's rubbing up against the block and you need to do some grinding.
You also can't use the connector that comes with the mini starter.
AMHIK X3

Keep going!

An adapter to install to allow the mini starter. I believe this is the item:

https://www.ebay.com/itm/204585346238?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=_gs8KNAgTSG&sssrc=4429486&ssuid=hb7jyuEyTLK&var=&widget_ver=artemis&media=COPY

 

[1975.Imperial]

Thank you, I've heard for a lot of people that it's a drop-in replacement, in the sense that there's no grinding required, other people say that there is significant grinding required. Is it pretty much based on excess in the block casting? On my (now broken) starter, I found that the plastic of the terminal insulator was to blame for the initial clearance issue.

Also, many people say to use an adapter for the terminals, but to me it seems like it would be possible to just remove the stock 'adapter' and use the terminals directly on the starter itself. Is there any reason not to do that?

My 'plan' for the installation is as follows:
-Remove stock terminal 'adapter' to use the terminals directly on the starter
-Add a DIY 'bushing' to the oversized top bolt hole (made with coiled up sections of a can)
-Figure out how to put the factory dust cover/shim back on as it seems to make a difference

 

[3175375]

Thank you, I've heard for a lot of people that it's a drop-in replacement, in the sense that there's no grinding required, other people say that there is significant grinding required. Is it pretty much based on excess in the block casting? On my (now broken) starter, I found that the plastic of the terminal insulator was to blame for the initial clearance issue.

Also, many people say to use an adapter for the terminals, but to me it seems like it would be possible to just remove the stock 'adapter' and use the terminals directly on the starter itself. Is there any reason not to do that?

My 'plan' for the installation is as follows:
-Remove stock terminal 'adapter' to use the terminals directly on the starter
-Add a DIY 'bushing' to the oversized top bolt hole (made with coiled up sections of a can)
-Figure out how to put the factory dust cover/shim back on as it seems to make a difference

I can’t tell you why the adapter is needed for a big block, as I have a 318. However, I suspect that it is needed to keep the starter cables away from the exhaust manifold.

 

[commando1]

I've heard for a lot of people that it's a drop-in replacement, in the sense that there's no grinding required, other people say that there is significant grinding required

I attribute it from which prison labor factory in China was it cast at. Some "supervisors" may crack the whip a little harder.

 

[1975.Imperial]

So I tried again, and the new starter bolted up with no problems whatsoever, I didn't even have to do any grinding. Now the engine finally cranks fast enough to start the car in cool weather!
Additionally, my rear drum brakes are giving me trouble, I think this summer I'll convert it back to rear discs (even if the rotors are a bit thin). The current drum setup had a runaway self-adjuster and completely shredded both the drum and shoes, and even after replacing them, the drum setup still just can't compete with full discs imo. I'll likely be giving all the nice drum parts to the Yorker, and getting as much new/rebuilt stuff as I can for the Imperial rear discs. One problem I'll have to sort out though is the parking brake shoe linings, I've heard that heavy-duty truck shops can re-line drum brakes, but I'll have to call around and see if anyone can do such small parts.
One other addition I made are some bull horns from the '70s. Evidently they're a bit ostentatious, but I got a great price on them and now people stop asking where my hood ornament is (they were actually cheaper than buying a new ornament). And before any angry comments roll in, I made especially sure to make this a reversible addition, no modification was done to the car to mount these. I made a faux-leather-wrapped metal bracket to suspend the horns above the header panel, the bracket bolts into 2 bolts under-hood, as well as the empty hole in which the hood ornament once sat, ensuring no damage is done to the vehicle from this addition.

 

[3175375]

So I tried again, and the new starter bolted up with no problems whatsoever, I didn't even have to do any grinding. Now the engine finally cranks fast enough to start the car in cool weather!
Additionally, my rear drum brakes are giving me trouble, I think this summer I'll convert it back to rear discs (even if the rotors are a bit thin). The current drum setup had a runaway self-adjuster and completely shredded both the drum and shoes, and even after replacing them, the drum setup still just can't compete with full discs imo. I'll likely be giving all the nice drum parts to the Yorker, and getting as much new/rebuilt stuff as I can for the Imperial rear discs. One problem I'll have to sort out though is the parking brake shoe linings, I've heard that heavy-duty truck shops can re-line drum brakes, but I'll have to call around and see if anyone can do such small parts.
One other addition I made are some bull horns from the '70s. Evidently they're a bit ostentatious, but I got a great price on them and now people stop asking where my hood ornament is (they were actually cheaper than buying a new ornament). And before any angry comments roll in, I made especially sure to make this a reversible addition, no modification was done to the car to mount these. I made a faux-leather-wrapped metal bracket to suspend the horns above the header panel, the bracket bolts into 2 bolts under-hood, as well as the empty hole in which the hood ornament once sat, ensuring no damage is done to the vehicle from this addition.

View attachment 654012
View attachment 654014

@mobileparts ? Can you help with his rear rotors?

 

[mobileparts]

Rear Rotors ---- NO ----
I had them beyond everyone else, but sold last pair 8 , 9 ,10 years ago... now.....

No one else EVER had them --- it was just an item that no one ever stocked......

He will have to send them to that outfit in Illinois that will beef them up and make them " new " again, like a crankshaft // or find used --- they fit
Late 1973 ( early 1973 were Rear Drum ) through 1975 All --- IMPERIAL..... They charge $ 400 & up apiece , plus shipping out and shipping back.....

I DO HAVE three (3) Last remaining sets of *** N.O.S. *** Asbestos *** Brake Pads for this application !!! And, as you and I know, that is
*** Especially CRITICAL , because this is N O T a Rotor you want to rip up to smithereens in no time !!!

Yours, Craig....

 

[Boydsdodge]

So I tried again, and the new starter bolted up with no problems whatsoever, I didn't even have to do any grinding. Now the engine finally cranks fast enough to start the car in cool weather!
Additionally, my rear drum brakes are giving me trouble, I think this summer I'll convert it back to rear discs (even if the rotors are a bit thin). The current drum setup had a runaway self-adjuster and completely shredded both the drum and shoes, and even after replacing them, the drum setup still just can't compete with full discs imo. I'll likely be giving all the nice drum parts to the Yorker, and getting as much new/rebuilt stuff as I can for the Imperial rear discs. One problem I'll have to sort out though is the parking brake shoe linings, I've heard that heavy-duty truck shops can re-line drum brakes, but I'll have to call around and see if anyone can do such small parts.
One other addition I made are some bull horns from the '70s. Evidently they're a bit ostentatious, but I got a great price on them and now people stop asking where my hood ornament is (they were actually cheaper than buying a new ornament). And before any angry comments roll in, I made especially sure to make this a reversible addition, no modification was done to the car to mount these. I made a faux-leather-wrapped metal bracket to suspend the horns above the header panel, the bracket bolts into 2 bolts under-hood, as well as the empty hole in which the hood ornament once sat, ensuring no damage is done to the vehicle from this addition.

View attachment 654012
View attachment 654014

Looks great, even better it is reversable. Watch out for the OPP, they my not think to favourably about the horns.

 

[1975.Imperial]

I was initially concerned about what the police would think, but after driving past 6 of them with no reaction, I think I'm likely in the clear.

A couple more things popped up with the car that'll need to be addressed. The first being the power windows. There's been times where none of the windows have worked, from any of the switches, then after driving for a bit, they start working again. What makes it even odder is that the power locks still work. I'm thinking that I'll start with replacing the fuse and see what happens from there.

Secondly, I'm getting sick of the Thermoquad and cast intake. I've been wanting a new Edelbrock carb and intake manifold for a while now and am planning on ordering them sometime soon. So far I've decided I want to go with the Performer RPM intake and AVS2 series carb. I'm debating between the 650 and 800 CFM models. I'm leaning towards the 800CFM, but would love some input into this as I've never sized a carb before.

By the end of this summer, I'd like to have a new Carb, Intake, 3" Dual Exhaust, 3.23 rear gears, a limited slip, and possibly a mild cam.

 

[Boydsdodge]

If your going to swap intakes, stick with the Edelbrock performer. The Rpm is taller and for a higher rpm, you most likely will run into hood clearance issues.
The AVS2 is a very good choice, don't forget to order the adaptor bracket for throttle.
What's going on with the Thermoquad?

 

[1975.Imperial]

If your going to swap intakes, stick with the Edelbrock performer. The Rpm is taller and for a higher rpm, you most likely will run into hood clearance issues.
The AVS2 is a very good choice, don't forget to order the adaptor bracket for throttle.
What's going on with the Thermoquad?

Thank you for those additional considerations. As for the height clearance, I was somewhat planning on swapping to the air cleaner from a 400, which should be 1" shorter. That combined with me not having hood insulation should provide enough clearance. I'll measure things to confirm though. As for the adaptor bracket, it's already on the shopping list.

The main issue with my Thermoquad is its unwillingness to start. For cold starts it often floods itself within the first 3 seconds of cranking, I have to get out and bypass the choke, then only most of the time it starts. Occasionally it won't warm start, and I'm stuck guessing if it's flooded or if it's lean. Additionally, the performance is overall poor, I know these things aren't race cars, but a little bump in power would certainly be appreciated.

 

[1975.Imperial]

Well, the new carb and intake have been put on pause. The muffler blew up during a hot-start last week, a friend actually heard the explosion from a kilometre away. Now I've got the car booked into an exhaust shop, I'm taking this chance to upgrade to dual 3" mandrel bent stainless. It's certainly not cheap, but it should be the last time it needs exhaust work of any sort.
Right now I'm driving around with it essential straight-piped, it sounds good, but is much louder than I'd like it to be. With the horns, the car's become maybe the most ostentatious thing on the road. That combo has, however, garnered some attention at the Import-focused car meets I attend.
One thing I noticed, without the muffler, the car starts up easier, oftentimes faster than a modern car. It's odd that a muffler would create enough back pressure to affect startup, but the current system is very restrictive.
Regardless, I'm excited to see how much the new exhaust changes things. The current exhaust is what I'm least proud of on the car, so it'll be nice to get rid of it

 

[Boydsdodge]

Well, the new carb and intake have been put on pause. The muffler blew up during a hot-start last week, a friend actually heard the explosion from a kilometre away. Now I've got the car booked into an exhaust shop, I'm taking this chance to upgrade to dual 3" mandrel bent stainless. It's certainly not cheap, but it should be the last time it needs exhaust work of any sort.
Right now I'm driving around with it essential straight-piped, it sounds good, but is much louder than I'd like it to be. With the horns, the car's become maybe the most ostentatious thing on the road. That combo has, however, garnered some attention at the Import-focused car meets I attend.
One thing I noticed, without the muffler, the car starts up easier, oftentimes faster than a modern car. It's odd that a muffler would create enough back pressure to affect startup, but the current system is very restrictive.
Regardless, I'm excited to see how much the new exhaust changes things. The current exhaust is what I'm least proud of on the car, so it'll be nice to get rid of it

View attachment 655442

2.5 " dual aluminized pipe with mufflers from Motivair in Elmira. The PF106 is what I used on my Imperial. Motivair Exhaust Canada Inc. - Custom & Universal Mufflers / Cross Sections, Resonators, Hot Rods
This will be good for your Imperial and last a long time.

 

[1975.Imperial]

Does anyone know if I can just wire in trailer lights to the factory taillight harness? As I understand it, the blinker system is a resistance based system, as such, are there any special considerations I need to keep in mind for installing a trailer light plugin?

It's also been a while since my last update, so here's one:
I got the exhaust sorted out, I ended up going to HotRodScott's and getting dual 3" mandrel bent with flow master 50 series delta flows. I'm very happy with it, performance and fuel economy have gone up by a lot, there is a significant amount of drone now though, so I think I'll get them to put on some resonators when I have some headers put on.
I also fixed the cruise control, as well as made a sturdier mounting bracket for the horns.
I've given the car another tune up too, this time it's closer to perfect, but still not there. The carburetor seems to be good, but I still need to work on the timing. I've added more base timing, but haven't had anything to limit the total timing, so I've been compensating by cutting the vacuum advance. The car drives alright, but I know this isn't a permanent solution, so I've ordered an FBO plate with springs. I'm hoping I can get a nice curve on the distributor with that kit

 

[CBODY67]

Are you desiring a normal 4-wire trailer connector or a 7-wire connector?

Most of the modern trailer wiring harnesses have a connector that matches the factory rear light connector, so it's a plug'n'play situation. Prior ones had to be hard-wired from the vehicle's wiring harness, I suspect. Of course, the 4-wire aftermarket harnesses were strictly hard-wired or ScotchLocked.

Due to the differences in the Imperial's front stub-frame and such, anything other than the factory HP manifolds might be an "Imperial Pain", possibly?

Just some thoughts,
CBODY67

 

[1975.Imperial]

Are you desiring a normal 4-wire trailer connector or a 7-wire connector?

Most of the modern trailer wiring harnesses have a connector that matches the factory rear light connector, so it's a plug'n'play situation. Prior ones had to be hard-wired from the vehicle's wiring harness, I suspect. Of course, the 4-wire aftermarket harnesses were strictly hard-wired or ScotchLocked.

Due to the differences in the Imperial's front stub-frame and such, anything other than the factory HP manifolds might be an "Imperial Pain", possibly?

Just some thoughts,
CBODY67

I'm trying to do a 7-wire, that way I have more versatility and the option to install a trailer brake controller. I already have one of the hardwire/scotch-lock types. I guess I'm wondering if I can just connect that straight to the existing wires or not

 

[CBODY67]

Trailer brake controllers can be done separately. As I understand it, the main advantage of the 7-wire can be its wider terminals and the "charge wire" in the middle.

 

[Rustyrodknocker]

I'm trying to do a 7-wire, that way I have more versatility and the option to install a trailer brake controller. I already have one of the hardwire/scotch-lock types. I guess I'm wondering if I can just connect that straight to the existing wires or not

You can connect or splice in to the rear lighting harness. How much trailer are you going to pull? I don't run a brake controller. I tow a single axle motorcycle trailer with two full size dirt bikes and gear. It was a tent trailer that I shortened and decked. No brakes on axle. This is about the max I would subject these cars to pulling very regularly.
The factory spring packs are weak in these cars and many fail in normal service.

I have had a couple fail. My 300 main spring was kinked when I got the car. It never had a hitch at that point. I built my own spring pack from two sets of factory C body spring sets.
I have retired the car from regular towing and if I was to start doing it every weekend, which I won't. I would order a new custom spring pack.