BUILD THREAD 84 Regal back half/caged/mini tubbed lq4/4l80e build

64nailhead said:

3.90 with a 26” tire will suck. 3.73 at a minimum. 3.55/3.42 would work fine.

3.73 with a 28” tire turns 2700 rpm’s at 65-70.’

Click to expand...

3.42s seem like the best bet with 26s, do you think they would be too low for the converter trying to get it going eventually with 29s, or when it downshifts it will have enough balls to get up and Go? Should I do 3.55s as a happy medium?

64nailhead said:

The difference between a 3.42 and 3.55 will barely be noticeable. I wouldn’t consider finding a rear that would be happy with a 26 and 29” tire mainly because there isn’t one.

Let’s back up, what cam are you using? Headers or stock manifolds? Stock compression between 9:1-10:1?

I read back through the last page. I’m not sure what tires you’ll be running that are 29”, but 28’s will work fine with a 3.73 at highway speeds, starting line ratio with a good converter (which you have.) If fin intended to put in a 28’s, then I’d pick a gear that will work with them and learn to live with how it runs with the 26’s for a short period. Keep in mind the converter will work differently with a different final drive ratio.

edit. : I found your cam specs on the 1st page. I’d say you want to keep your cruising RPM above 2200-2300 at a minimum.

Click to expand...

Long tubes, tall intake manifold, 6.0 lq4 bored .20 over, with 243 heads, compression should be around 10.2-10.5 depending what head gasket was used, which I didn’t assemble, most likely gm.
I can only do 29s in sportsman’s, the 28s only go up to 12 inch wide, 29s go to 18.

In od, at 2300 rpm, there’s about a 10- 15 mph difference between 26/29 and about a 300 rpm
Cruising difference 26s would be a bit under 2600 rpm in od with 3.90s, and 29 would be a bit under 2300 rpm at 70, I can live with that.

So 3.55 would still be too low for 29s, and the lowest end ratio for 26s. I’m leaning towards the 3.90s now, in od Thank you for your input btw!
After driving with 4.88s, It’s scarred me from going too high hitting the rev limiter in od 🤣 but that could have just been the combination of trans slipping as well, I never really got a good feeling for the car yet because of that reason, and I just don’t want to run out of gear or be screaming down the the highway at 70 at a crazy high rpm

I get the trans back tomorrow, a lot of billet parts, transgo shift kit, new clutches, bushings band, etc.

I ran a new return line from cell to engine bay, ditched the c5 ffr, in place installed a summit 10 micron inline filter, and a Holley fuel pressure regulator from Summit, the first regulator I got was pissing from the right side fitting, I couldn’t get it to seal, I ordered another one, and the same exact thing, only the right side port. I tried the Mr gasket fittings, and tried the summit fittings, 3/8 npt with sealant, for the hell of it I switched the ports and plug right to left, flipped the regulator upside down, and it seems to seal fine now after tightening it little more by little, it’s rock solid at 59psi now. Fitech calls for 58. Fuel
Trims all went down since it was dumping alot of fuel and my eyes are no longer burning running it in the garage.

I’m bringing the differential in 2 weeks to install
The trutrac, new bearings, and 3.90s.

Hopefully after this it should be good to go and finally be able to enjoy it!

Rktpwrd said:

Just a heads up, some fuel pressure regulators like my Aeromotive one use ORB (O-Ring Boss) fittings, not NPT. Check and make sure yours aren’t like that.
Nice progress!!

Click to expand...

Yeah I checked 5 times, they’re definately 3/8 npt, I contacted summit to return these, and bite the bullet for the aeromotive since that’s what they use, orb, I feel like they would seal better, for that price they better!

picked up the trans, popped it in, adjusted the new shifter, indexed the dipstick 1/4 inch above the machined surface, poured 2 gallons of dex 6 in for
Now, going to wait to top it off when the diff is in and I can go through the gears, ran some heat shield wrapping on a few things, replaced the original cheap fuel cell cap, with a new cheap aluminum one lol atleast this one seals now, after reading for 3 hours of harnesses vs 3 point regular seatbelts and risks with cages/seats/4/5/6 point, I ended up ordering 2 sets of non retractable standard mount 3 point belts, since I’m using regular seats, and the main hoop is pretty far away from my noggin. and all is well, diff is getting done next month, getting a parts list together for it, order the Mickey Thompson sportsman’s 15x18x29s for the 14 inch weld knock offs around summertime and it should be good to go!

I may just wrap the car with gloss black vinyl eventually as well, the car is not worth the body work, but I don’t mind the 💩box look since I know what’s underneath it 😁

found driver side lower quarter panel, going to cut it out, weld, and fill it, I don’t think the company is a sponsor so I’ll refrain from mentioning the brand

Ps I know the regulator should be 6 inches forward of the firewall, but for now that’s the most convenient spot for it 😆

bracketchev1221 said:

We put the 18X29 sportsmans on my friends car. He likes them and they fit will in the stock diameter wheel well. They are on a 14" wheel as well.

Click to expand...

Found some pics of that setup!

I hate to go back to the gear question, but does this make sense.
If I switch from the 26 inch tire to 29, say with 4.10s, The 29 inch tire would act as if it has 3.73 (3.67) gear ratio compared to the 26s?

It would be gear ratio X old tire size divided by new tire size?
4.10 X 26/29?

I feel like that’s a decent rpm to mph ratio, comparable to like you said a 26 tire with
3.42-3.55 which comes out to around 65 mph at 2300 rpm

So 4.11s, or even still 3.90s give or take 4-6 mph, may be my best option for an all around street car with the 29s. thanks for bearing with me, its making more sense to me once i started doing the comparisons and math between them aside from just general knowledge of it.

I’m going to go with 4.11s considering the wheels going on it, and when the tc locks it’s going to drop another 200 rpm.

also found my solution to matching wheels,
Going with the vision sport lites in the front Chinese knock offs of the drag lites, but they have standard machined bores for regular lug nuts, no drilling/tapping/machining studs to get them to fit up.

For the rears, I decided to go with the Hoosier pro streets instead of the mt sportsman’s, I like the old school look tread pattern compared to the flame look on the mts, and a tiny bit more bulge on the sidewall.

They will look like this but on 14inch wide drag lites, size will be 29x18.5x15

I’m excited to finally get the look and stance I’ve been imagining with them tucked nicely underneath.