i want to swap a 350 h.o. into my 91 rs. it currently has a 305 with a edelbrock carb. so i already have my ecm stuff removed, msd distributor, new fuel pump, etc. my question is, can i swap my serpentine setup from the 305? which harmonic damper should i use? ive never swapped a motor before, but i know that the h.o is a 1 piece rear main seal, which is good cause it'll bolt right up to my t-5, but do i need to buy new bolts for that (for durability)? is 750cfm too much for that motor? any help would be appreciated.

 

The 330hp H.O. I assume this is what you mean or the zz4?

 

the 350 h.o/330hp crate motor

 

Im not sure about the belt system.I think it works.Someone please correct.The 750 is to big if you keep the stock cam in.A 750DP was way to much for my zz4.I think 600-650cfm would be good.

 

i was thinking the same as far as the carb selection. i really need an answer about these pulleys!

 

A 750 isn't too big, but with a manual transmission you'll want a double pumper. You need to size it based on the lowest RPMs at which you'll go WOT (there's a chart on Holley's website to determine that). Most likely, a 650 will be adequate and won't cause low RPM WOT problems.

You don't "need" new bolts for the flywheel or clutch, but it can't hurt.

The serp accessories will fit. You may have to drill & tap one hole in the passenger head - mount everything, mark the hole, take it off, drill & tap. If needed - I can't say I'm certain about that, but have heard of it on ZZ4's).

 

650DP is what I have on my zz4 and it is perfect!!!

 

Some info about the 350 HO Deluxe that may be helpful. The motor is equipped with a 4160 600-cfm Holley with vac operated secondaries and electric choke. If you use headers, you'll need the ZZ4 dipstick: P/N 12551144 (Indicator), P/N 12551154 (Tube), P/N 09439930 (Bolt). I used GM's lightweight flywheel (14088646). On the HO Deluxe, the manual recommends the accessory drive brackets from a 96-98 L31 Chevy or GMC truck.

JamesC

 

Good scoop, JC.

Most people assume "bigger is better", which isn't always the case, so the factory and Holley are nervous about misapplications, which is why the VS carbs exist and are suggested/supplied. But, with proper stall (the biggest problem with over-carburation), a DP will do just fine and perform better.

Now, does anyone know the difference between '88-'92 3rd gen accessory mounting and '96-'98 L31 Chevy or GMC truck accessory mounting????

 

True that, the 350HO came with the worst dipstick ever produced. What a piece of crap...

...thats 2 votes for the zz4 dipstick!

 

I LIKE TO HAVE A 350 HO WILL THAT WORK ON TPI AM LOOKING FOR 400 HP HELP

 

good luck, plan on spending another 500 dollars for a vortec specific TPI intake, then you'll want siamesed runners, there's another 300...plus you'll probably have to bump the compression, and add an LT4 hotcam...don't forget learning to burn your own chips...

all in all, including tuning the thing, you'll drop a great deal more money trying to keep(or get, i didn't see if you already had tpi) a 350HO w/ tpi.

400HP out of a 350HO and TPI isn't going to happen, IMHO.

get an vortec RPM intake and a holley 650DP and call it a day. Then you can take the extra 1.5-2k you saved on TPI junk and get a new transmission...I know I need a new one now

 

hey nick thanks for hijacking my thread. i planned on using a carb on the 350 h.o.

 

A lot of people think that carbs can be too big or too small but as long as you know what you're doing or paying somebody who really knows what they are doing, they can tune it so that you can't even tell the difference. I think that carb will be just fine as long as it is tuned right.

And as for the random tpi thing, I am trying to sell a tpi setup with everything from fuel rail to intake manifold for $350