I have a 5.7 350 w/ TBI (1987-1995). It was a crate engine purchased about 10 years ago (it lives inside a 1984 suburban k20 4x4).
9.25:1 Compression ratio
With these exhaust headers (Hedman 69090) --
Okay, the questions .....
1. How large (diameter) should my exhaust pipes be? (2.5", 3", etc.)
2. Should I use an "H" pipe to connect the two banks, or just have each side of the engine be completely independent?
3. Where is the best place for an oxygen sensor?
4. Would Flowmaster Super 10 Series Mufflers be a good idea? If not, what would be better?
5. Should I have 1-in-1-out or 1-in-2-out mufflers?
6. What's the best catalytic converter for this vehicle?
FAQs:
- I want a good sounding, loud exhaust -- not loud stupid, but loud deep
- I care more about sound than off-the-line acceleration
- I never tow anything, but often do freeway driving
- I do want to pass emissions (Arizona)
1. For your setup, 2.5 inch pipe will be plenty and adequate.
2. You don't have too, you can if you want. It does make servicing your transmission a tad more difficult. I opted to not use one and it never caused me any grief.
3. Driver side collector or just after the collector. Had no issues with mine being there, just found the best place for it with linkage and had no issues. If it's not a heated 02, I would recommend installing a heated O2, it helps with moisture, reading accurately and is better for engines with headers, especially full length like yours.
4. I used flow master super 44s, they were healthy sounding during normal driving, pretty much faded off at freeway speeds and were pretty quiet, sounded awesome when I goosed it. Only problem I ever had was idling for a while like when in a drive thru but I had mine dumped over the rear axle and pointed at the ground so going all the way will eliminate that issue. I've also heard MagnaFlow's and Borla's mufflers with nice sound. If I was gonna build another system, I would possibly look into one of those. Then again, Flowmaster is always a classic.
5. That's dependent on which setup you choose. If you do independent sides, then 2 mufflers, both 1-in-1-out. If you do a different setup then it depends on the arrangement. Mine was independent true duals, 1-in-1-out.
6. There are alot of cats out there that are efficient. I've heard good things about MagnaFlow's cat converters. Not sure what else is out there.
I had a TBI 350 that was bored, cammed, with aluminum heads, the whole engine was built top to bottom, my exhaust was simple, affective and clean. So your current setup and goals are similar to what I was using.
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