Thread: newbie sbc400 question

Tweet

Hi, i'm new to the forum and have a question, i currently have an86 regal with a sbc400,w cam and intake/th400,w shift kit: but i'm still not satisfied with it's performance. I don't want a race car just a little more excitement from the pedal. what can i do to provide the best bang 4 the buck?

Cam is comp cam 12-211-2
intake- edelbrock 2101
rebuilt q-jet

Thanks for any help!

What cam, intake, and rear gear do you have? A lot of these cars had like 2.70 rear gears, guaranteed performance killers!!!! Just changing it to a 3.50 ration makes a huge difference in performance.

After the gears a set of headers will help.

A better cam. Your cam is very mild.

the intake carb and cam are all listed and i forgot to mention i already have a set of shorty headers installed(flowtech) and i'm not sure about the gears i'm sure its the stock gears that came with the car it had a v-6 in it.

the cam was recommended by the guy at the local speed shop he said it would provide the best low end power with the intake i had purchased..will a bigger cam still provide low end power?

Gears are probably the biggest thing. If you're trying to run a 2.70 rear-end ratio, you'll still feel like your lugging a tank around behind you. A 400SBC will make plenty of torque with that cam. It's the cam I'm planning to use in my 377SBC. It was also recommended to me by a professional engine builder for good low-end torque and also the biggest cam available for a stock converter.

I'd at least pull the rear cover and count the teeth to establish what ratio is there. If you're under a 3.00 ratio, it might be a good idea invest in a set of gears....maybe a posi unit if you have the budget for it.

A little off topic, but that big TH400 behind your motor is eating up some power too. They are heavy heavy heavy and eat quite a bit of power compared to some lighter duty trannies like the TH350 and 700R4. I'm not suggesting that you change the tranny out by any means because the 400 is an incredible piece of work, but that could help explain as to why your not getting the giddyup that you'd like.

Originally Posted by sbc400Regal

Hi, i'm new to the forum and have a question, i currently have an86 regal with a sbc400,w cam and intake/th400,w shift kit: but i'm still not satisfied with it's performance. I don't want a race car just a little more excitement from the pedal. what can i do to provide the best bang 4 the buck?

Cam is comp cam 12-211-2
intake- edelbrock 2101
rebuilt q-jet

Thanks for any help!

If you have the stock comp. ratio I would not put a larger cam in it.
Like other people have said what gear do you have?

Just a note to go along with Hopper's idea. THe THM400 has heavy internals to spin. Closer gear splits and not evenly set on the planetaries. It requires more torque to drive the unit under load. Take the gears down to a more suitable set (3.50?) and strongly consider a different tranny. Q-jet is set up for???? They can be tuned to bring this set up around big time.

Originally Posted by nitrowarrior

Just a note to go along with Hopper's idea. THe THM400 has heavy internals to spin. Closer gear splits and not evenly set on the planetaries. It requires more torque to drive the unit under load. Take the gears down to a more suitable set (3.50?) and strongly consider a different tranny. Q-jet is set up for???? They can be tuned to bring this set up around big time.

With all the torque the 400 sbc makes I don't know if you would ever feel the differance but you might notice it at the track.
Keep in mind this 400 sbc is swinging a 3.75 stroke the same as the 396/402.

I'll have to wait till it comes back from the shop to check the gears; but i do have a th350 laying around that i had purchased for my regal but when my mechanic found out i had a th400 also he said i should run the th400 behind my motor, you guys think it would help if i had the 350 built and installed behind my motor. and as far as the q-jet my mechanic tuned it a little when i took it back; now i'm just trying to decide on what step to make next i think it's gonna be the gears how much do they normally cost?

Fuel curves will change with gear swaps. Go forward with gears and then you can adjust and tune for your app. You might like the THM400 for your daily use. It's all a matter or perspective. Gears can be bought for as little as 100 or as high as 280. shop around. Sounds like your setup will be more than affordable. Patience is the key when setting up. There are plenty of posts on this site to show you with pics and specs to guide you to get it right. If you have doubts about set up, use a buddy, a shop or come back here and dig in with research. You will get this right with all the resources.

Assuming that your gear set is pretty high, I suggest that you consider a lower gear like a 3.73 and then change the transmission out to an overdrive such as a 700R4 or 200 4R. Lot of good info on those here: http://www.bowtieoverdrives.com/index.shtml. Whether you buy from them or not.

By making these changes you will notice a huge improvement in the seat of the pants feel you get because the OD transmissions have a much lower first gear. That combined with the lower rear end gears will give you the feel you want. Then with the Overdrive high gear, you will still have the low RPM cruise for economy and reduced strain on your motor. If you have to do one before the other, I would change the transmission first, then the gears.

They have charts on the Bowtie Overdrive page that will help you calculate what your gear ratio is based on tire diameter, speed and RPM so you won't need to pull you rear end apart to figure your geaar ratio. You will need a tach to do that.

Pat

It depends on what rear you have. I'd say $100 and up for ring & pinion. Then there's bearings, shims, seals...etc could be another $75 and up. It all depends on what you have and what you need....

Originally Posted by nitrowarrior

Fuel curves will change with gear swaps. Go forward with gears and then you can adjust and tune for your app. You might like the THM400 for your daily use. It's all a matter or perspective. Gears can be bought for as little as 100 or as high as 280. shop around. Sounds like your setup will be more than affordable. Patience is the key when setting up. There are plenty of posts on this site to show you with pics and specs to guide you to get it right. If you have doubts about set up, use a buddy, a shop or come back here and dig in with research. You will get this right with all the resources.

You know nitrowarrior you look a lot like John Force.