I have a 89 TPI 355

Stock Pistons
60cc Aluminum Edelbrock heads
Hi Flo Runners
52mm Holley Throttle Body
Thermomaster Chip
160 Thermostat
Comp cam with .464/.470 Lift Non-Roller


I have 1.6 comp cam roller rockers... I was wondering if this would help me any or hurt me..
Also i have 26lbs. Injectors, but i told this was to much.
I have not put these on yet, i was just asking for suggustions or what else i could do for some extra power. The motor has just been rebuilt and has about 400 Miles on it.
Thanks for all of your help!!

 

The 1.6 ratio rockers should be OK with your 355. They will help you by making the valve see more lift with the same duration. Just make sure your springs can take the extra lift and you are set.

26lb injectors are fine for a 355. Anything larger may be pushing it. Just remember when you change your injector size you are going to need a custom chip. The PROM has an "injector constant"that needs to be set to the proper size to work right. For the mods you have done, I would not even bother with the injectors. Save them for later down the road if you continue upgrading

 

I agree, don't put them on . Your car will think you still have the old 22lb'rs in it . So it will be rich all over. Which is not a good idea

 

Actually You may be better off with an adjustable fuel pressure regulator than the bigger injectors. Get an AFPR and a decent guage and test various pressures with the best results. Stock is 42, the best for a streeter seems to be around 46 and for hard running 50 seems to give a little more boost. All without messing with the computer

 

Increasing fuel pressure along with bigger injectors all without any changes in the PROM is going further in the wrong direction. If you can't do the tuning, you better stick with the stock-rated injectors.

 

Read closer, I suggested the AFPR instead of installing the larger injectors. And how is getting the AFPR without changing the PROM going farther in the wrong direction? It is an easy way to "tune" without doing PROM programming.

 

Injectors seem to be a point of confusion for most. Until there is some serious work done to the engine, you really shouldn't be upgrading them.

 

Thanks, this is the point I am trying to make! Whew! Stock injectors are supposed to be good about 350 HP or so, right? This is what I heard anyway

 

...good working stockers are good for around 425hp. TPIS has run them as high as 430 something....

- yes, stick with stockers, get the afpr and bump your psi. - Have you ported the intake plenum? Base? - headers/full exhaust?

 

[quote=Shagwell]...good working stockers are good for around 425hp. TPIS has run them as high as 430 something....
quote]

True, but you may want to take a block of salt with whatever TPIS propaganda you read (not a grain but the block salt).

 

Another 355, love it! I have a reman 355, with 2500 or so miles on it at the moment. It has all the 305 TPI stuff on top of it. So basically I have a big cube 305, at the moment. Check my sig for what's already done.

To answer your question, I'll tell you what I'm going to do. I've researched the living hell out of these mods and I am confident they will work well (for me at least). The stock air can was tossed in favor of an open K&N; MAF left alone; going with a 52mm TB; AS&M LTR's; and Edelbrock (better duck when you say that) hi-flo manifold; I have a Holley AFPR I'm gonna use; I am going to port match the plenum-to-runners-to-manifold; I will be plugging in 30lb injectors and I will run them at 48psi (give or take depending on the tune). Topped off with a custom chip from pcmforless.com. I will be taking it to be dyno'd, hopefully dyno-tuned, I dunno yet. All the intake stuff will be polished, lookin' good!

All that good stuff is probably gonna run be $2100 or so. It will be money well spent when my 355 drives like a 355 insted of the motor that came in the car.

Good Luck...Eric

 

Yes, headers, gutted cat, flowmaster 40 3" all the way back, i did grind the walls behind where the throttle body bolts on...