unbroken

OK, I have searched and read dang near everything about aftermarket performance exhaust, and finally settled on the Dana's. SO I call them and they tell me they do not make the danas for the small block so I am back to square one.

I built a pair of 383's and stayed with the stock exhaust. I went with Bowtie heads, 1.6 ratio roller rockers, reground the cam, (probably should have went a little bigger) and had them retuned. I am GPS'ing at 66, and just went to 23 pitch Revolution 4 4blades but I am only turning them at 4800-4900 rpm's. I plan to lab the props after the exhaust. My question is what exhaust is the next best thing for the small blocks. I want to keep my Q&Q exhaust, but would like to see a gain in performance. I picked up 10 MPH GPS over the 6.2's. Do ya'll think it is realistic to see 70 with the right exhaust and the lab finishing?

Dangerous Dave

I put Stainless Marine on my cig with small blocks. I'm very happy with them. I had them make full length tailpipes but I'm pretty sure with the stock bravo system you could use your q&q. In addition to helping your motors breathe better, you'll save a bunch of weight, eleminate the chance of a leaky riser gasket and reduce your chances of reversion. Give them a call, they're very good at what they do.
CMI also makes small block headers but I have no experience with them. I believe Stellings makes small block headers also.

I would think you will be really close to 70 with just the labbing. Just out of curiosity, did you dyno the motors, and if so, what rpm is your peak hp? The people at Throttle-up propellers can really help you if you don't already have a prop guy. A couple phone calls and a few grand and you'll be in the 70's for sure.

jmherbert

I would invest in some aftermarket exhaust such as stainless marine or revolutions, just for the reversion factor and more importantly the dry joint.

After 2 teardowns due to a leaky manifold, I put revolutions on mine and never looked back. Don't know if there was much performance gain, but I know they'll never leak thru the riser/manifold joint because there isn't one.

pullmytrigger

I put Revs on mine....very happy with them.....definatly more low end/midrange and saved 100lbs per side.

formula 382 sr-1

iTrader: (3)

I have Stainless Marine on our 272 formula 383's with 425hp on dyno 69.8 on gps. Had the tail pipes lengthend 10 inches. The cam I am running is 223/231-530/548 @ 110 center line no reversion. 272 FORMULA FOR SALE

Ryan00TJ

iTrader: (8)

What are the specs on your cam? Roller or flat tappet? Depending on cam specs, your not getting the full potential WOT at 4900rpms. I think it's very possible to hit 70 with an exhaust change and labbed props. You will likely pick up 2mph and some rpms with the props worked on. Maybe 2 mph with the exhaust upgrade. It kinda stinks as it's a very $$$ trial and error thing. You might get more than you planned and then you might not.

I'm currently running 1992 era Glenwood aluminum HP manifolds and FastGlass 4" Stainless 16" long risers.
I don't think either company makes these anymore.
AFR 190 heads, 226/230 .537/.511 112LSA hyd roller


Alot of nice choices out there.... EMI Thunder, Stainless Marine, Rev. All will give a comparable performance increase over a stock manifold and save alot of weight. As to which one is better, it's all speculation as there is no hard proof. That is the part of this hobby that burns my A**, no boat magazine will do a non bias exhuast shootout and see which one is better.

I do give props to FTM for doing this testing on the 496's!

Plum_Crazy

More money, but CMI E-tops are my choice.

DKerns

Running the stainless setup on my SBC. The boat had a "Blown Up" 383 when I bought it. Running them on s standard 5.7 now.

unbroken

My cam is the same that came with the 6.2's, but it was reground by crower and I switched to 1.6 rollers. It is a roller cam, and yes I left some power on the table when I used that cam, but I was/am more interested in reliablity, and longevity, then the peak power it can make. That being said, I want to maximize the power that I can get with the exhaust. The heads are 190's, and they flow excellent. I have already picked up 10 MPH GPS over the mx 6.2's, and moved from 21 pitch 3 blades to 23 pitch 4 blades, and they are not labbed, nor am I spinning them. Bob at full throttle dynoed them, but they were having injector issues, and at 4700, the knock sensors were pulling 26 degrees of timeng, so they were showing a top of about 360ish, with those problems. I think I have the injector issue solved, and the knock sensors are fine. I am guessing 375ish with stock exhaust. Thanks for the help guys.

unbroken

Do you know what cam it is?