Have a 78 small block 355 tpi with a set of 305 h.o. heads.. hyd comp cam (12-242-2). rebuilt bottom and top end. runnin 30#injectors. will a set of 2055 headers w/ air tubes and y pipe with high flow cat and magna flow 3 in catback( single cat) hurt my motor or will i just be loosin a couple extra horse power compared to a true dual(2 cat with x pype)?just ordered the cat back today... can i use this for wat i have or will it be bad for my motor??? please help. already have my new ecm and prom tuned for emmisions from aztpi. last is wiring harness.. then im done. gotta have it running by march 27..

 

Those headers will be fine along with a 3" single exhaust. More power could be had with long tubes and or 1-3/4" shorties but the hassle of fitment, fab work, and rareity of 1-3/4" headers, might make it not worth the effort. Dyno Don may make a set that you might want to look into.

 

so the 2055s are not 1 3/4in and a shorty? i need airtubes and coated. wanted long tubes but need to pass emissions.

 

The type of header you chose has less to do with emissions than the overall tune of your combo. If you are worried about emissions you should leave your car stock and or take some time to reasearch a good "tune-able" combo that will make the sniffer police happy. Make sure you use a 3 way cat with AIR tube.

The 2055's are non coated 1-5/8" shorties with a 3" y-pipe. They have AIR tunes and are a really good set of headers. You can send them out to have them coated at a reputable coating shop. Most headers do not come coated, and if they do the coating is often poor.

 

well i want 1 3/4 inch. shorties. coated i was gonna have them coated by summit, then sent to me.everyone talks dyno dons headers.?

 

The only shorties you are going find in 1-3/4" are used SLP's and or new dyno dons. I have heard nothing but good things about dyno dons headers. I would plan on having your headers coated after you buy them. Headers that come "coated" are often done poorley. There are many companies that do a fantasic job at ceramic coating. Jet Hot is one and American Coatings is another. I am sure there is a coater within your state as well.

 

where can i get dyno dons?

 

A quick search on this website . His user name is the same as his product.

 

Hey thanks alot man.got a hold of him. Be ordering mine next check...appreciate the advice..

 

Why such big injectors? You will probably be fine with a 3" single ypipe too.

 

Goin hsr. After its runnin and I get it to pass emissions. tpi is temp.

 

Just wondering. Did you already upgrade the stock 305 heads valve springs yet? Did you get your tune set up for hsr intake with the 30lb inj?

 

The 350 heads would flow more you know. You would be putting out 300 hp +, if you put on some truck Vortec heads and changed your tpi base to the scoggin dickey one, you know.Are you going for a street car or a high rpm track car?

 

No. To my intake.The people at az tpi are takin care of me.Though.Ya new lifters valves springs. the whole Kit from summit.

 

Well ,i hope you keep us posted on how it goes. I am curious to see what kind of gains you will get with the HSR.

 

Ya I know didn't wanna have to swap heads. Keepin as is till its up and running because I have not even driven this car yet. Had it for a yr and procrastinated to the last 3 months i have done.Headers. Exhaust .ecm. prom and tune cam and lifter set. New painless harness.injectors. fuel pump.water pump.balancer . New paint job on motor. Next is rear end.hsr.heads

 

What gear are u running now?

 

sounds like you are ready for some nice heads.

 

Well the car originally is a 90 rs. and I haven't exactly checked but has a ten bolt in the back.gotta run the numbers to be exact

 

Heads wouldtop it all off and be huge.I just wanna get it runnin first. Car deff has potential.

 

And street car. For now. Hsr and rear end plus heads then track car. but that's not for couple months. My new daily driver will be and 87 vette.(sorry not a maro) but close great deal... hopefully 3 months

 

just check your rpo codes in the rear hatch door. Should say somethoing like gu2, or gu5. Look for that combo.

 

Rear hatch open.where abouts ?

 

open your rear hatch and look to the left at the sail panel, there should be a little plastic door with a key/lock. In the cargo area, if you were to look to the right then that side holds the spare tire behind it.

 

Basically the little storage compartment in your trunk. You open it with your trunk key

 

Ya but n gu2 or gu5

 

It should be in there. Gu-something. Look again

 

GU1 : AXLE REAR, 2.41 RATIO

GU2 : AXLE REAR, 2.73 RATIO

GU4 : AXLE REAR, 3.08 RATIO

GU5 : AXLE REAR, 3.23 RATIO

GU6 : AXLE REAR, 3.42 RATIO

 

BW 9-Bolt RPO Codes:
GH3 = 2:77
GW6= 3:27
GM3 = 3:45

look for those too. Maybe you have a 9 bolt rear!

 

Let me know dude.

 

there is ten bolts will check codes when back home