l03 engine, l31 cam?
 

Hello, I did my best to scour the message boards and I'm sorry if this has been asked before but I have an 88' Formula bird with the l03 305 and was looking to put some more horse in her. I was wondering if you could put a l31 cam in without any/many problems and what kind of heads I should get to support the system.
The total system I plan on *eventually* putting in is hooker headers, high rise/dual runner intake manifold, new cam (idk what one yet) and new ported and polished heads (also don't know what kind yet) along with a new cat back dual exhaust and some form of ram air intake
I'm new to the site and new to the muscle building scene so i'm sorry if some sh*ts effed up, or i don't know much.
Thanks alot in advance

Re: l03 engine, l31 cam?
 

The general cheap cam swap on here for the L03 is a LT1 cam. It has a lot better specs to it then the L31. Either one you will have to do computer tuning or change to a carb and tune it. The L31 cam isnt much bigger than stock. It may run ok with stock tune, but I don't think it would be worth the time of swapping it for the minimal gain. You can usually find a used LT1 cam for under $50. I'd say the vortec heads are one of the best values out there at about $600 for a complete set. Which is what I went with. That combo with good intake and exhaust setup can get you close to 300 hp at the crank. You could always go bigger and better but that's a decent setup.

Re: l03 engine, l31 cam?
 

Before doing a cam swap you should have a full exhaust ready to take full advantage of it. If you start with headers, high flow cat and catback you will notice quite a gain from that alone and really dont need to worry so much with computer tuning until later. A cam swap is much more involved and will require you to learn much more and tuning will become an issue.

Re: l03 engine, l31 cam?
 

Also, if planning to go with vortec heads it may not be a good idea if you need to pass strict emissions. EGR may become an issue if you need to pass smog and will require a more expensive manifold and some fabrication. If retaining EGR is not a problem they are a good option.

Re: l03 engine, l31 cam?
 

So an LT1 cam should drop right in? Also what do you mean by, and how do I tune the computer to match the new LT1 cam? So far I can keep my car running when she breaks but a lot of this is new to me. Would you say a magnaflow catback setup should be sufficient? also whats this i hear about open element air intake instead of cold air intake, whats best for my fuel mileage and power?

Thank you for the help!

Re: l03 engine, l31 cam?
 

Could I just hollow out my cat instead of getting a high flow? or maybe straight pipe it... also is 3' pipes from the Y back gonna be sufficiently large enough to work this.. One last question, Will doing all of this make my gas mileage go horribly down or hover around the same..?

Re: l03 engine, l31 cam?
 

Do some more research on the site and poke around in the tech general/tbi forum. Heads and cam swaps on a 305 will give you more power but the easier alternative is to drop in a 350. 3'' exhaust from the cat back is fine for the car and hurt anything. Before you consider a cam swap get your headers and that end dressed up to make the most out of whatever you choose.

Re: l03 engine, l31 cam?
 

Its against federal law to remove or modify converter. Not that I care just letting you know!

Re: l03 engine, l31 cam?
 

Yes the LT1 cam will pretty much drop right in. Only mod to the cam is you need to make the dowl pin on the end of it the same length as your stock cam. Any aftermarket catback will work, just pick your sound and go. If you dont have emissions then nobody will be checking your cat or emissions equipment. But you will not find a shop that will touch it though, gotta figure that out on your own.

You have to get into prom tuning to do it on your own, or take it to somebody. I got tired of it and ditched the tbi for a demon carb. Plus everything I have put on my 305 will directly cross over to a 350 if the 305 decided to let go, so I'm just running it until it dies or has a major issue. But it loves 6k rpm everytime.

Re: l03 engine, l31 cam?
 

If you're sticking with the stock heads then the LT1 cam is good for you. From my experience though I wouldn't even bother with a cam that small after going to the ZZ4 cam. It really isn't that hard to tune in and the power increase is very nice. Then again I did the whole Head cam and intake swap at the same time. Plus, go to page 3 of my cardomain and read up. I'm not typing all that mess up again,lol

Re: l03 engine, l31 cam?
 

Out of curiosity what kind of gas mileage do you get with the zz4 cam and vortec heads? Also what do i need to use to tune the car once i get it all?

Re: l03 engine, l31 cam?
 

I don't have Vortec heads, i have mildly ported ZZ4 heads. My mileage went down a little bit but nothing a little more tuning shouldn't fix.

Re: l03 engine, l31 cam?
 

So the current setup i'm looking at is LT1 cam, vortec 059 heads, Hooker darkside headers and a 3704 intake from edelbrock.
Do you think that will all work together? also how much HP do you think i'll land at. i'm hoping above 220. What equipment do i need to start tuning?

Re: l03 engine, l31 cam?
 

you should make well over 220 hp close to 300 at the crank

Re: l03 engine, l31 cam?
 

sweet!, about how much does that translate to at the wheels?
Also do you think all of the head and cam will fit together in the intake and block and all that without too much machining? I'm very new to the scene and would like to do as little custom fabricating as possible for my first cam/head/intake swap

Re: l03 engine, l31 cam?
 

I agree it should put you around 280 or more at the crank if tuned well enough. I had planned to do the same setup, but have changed it a bit. The 3704 intake is not going to bolt up to those heads. You will need a vortec specific intake. Its probably best to find a vortec carb intake and get a TBI adapter plate. There is only 1 TBI vortec intake from GMPP and its around $400.

Re: l03 engine, l31 cam?
 

:yup: You'd be good with the Vortec specific Performer RPM intake with an adapter.

Re: l03 engine, l31 cam?
 

Yes, but watch for hood clearance with the Performer RPM as it is a high rise intake.

Re: l03 engine, l31 cam?
 

If it doesn't fit what can i do to get a little more hood clearance?
So in total i should get a vortec 059 (305?) heads, LT1 Cam and a performer RPM intake from edelbrock with a carb-TBI adapter plate?

Re: l03 engine, l31 cam?
 

You have many options. You could play with shorter air cleaners & drop bases. Change your hood. You could also go with a low rise vortec intake. There are many to choose from like the regular Edelbrock Performer Vortec (shorter than the RPM), Weiand, Professional Products Cyclone, Summit, etc.

I have the stock intake with a 3" x 14" open air cleaner and my wingnut hits the hood insulation with the stock hood.

Re: l03 engine, l31 cam?
 

I'd do a full exhaust with headers back first. Once you have the rest of your parts you may want to look into the EBL to tune the combo. Probably the best way to go.

Re: l03 engine, l31 cam?
 

Whats an EBL? Also one thing i was curious about, what kind of gears should i get, I was thinking 3.73, I want to gear it mainly for gas mileage but off the line i would like to boil some tires if necessary

Re: l03 engine, l31 cam?
 

Also does anyone have any idea where the "spid" sticker with my "rpo" codes are? i looked in my console box and in my rear lock box i seem not to have them....

Re: l03 engine, l31 cam?
 

the L31 cam is the B-body lt1 cam.

Re: l03 engine, l31 cam?
 

honestly, it sounds like you have a lot to learn before you go messing stuff up. a cam and all that other work is very intensive and does require experience and knowledge.

Re: l03 engine, l31 cam?
 

I'm going to be having someone who has done cam swaps etc before help/watch over me while I do this but I want to make sure the stuff I picked out will work together. What better way to learn than by doing?

Re: l03 engine, l31 cam?
 

I assumed he was talking about the L31 vortec motor cam out of the 5.3 trucks.

Re: l03 engine, l31 cam?
 

The L31 is a 5.7 SBC.

Re: l03 engine, l31 cam?
 

The EBL is a board with software that you can plugin to your computer to assisting in tuning. It allows you to program the computer without changing chips. It also makes tuning much easier with the VE Learn function. Bottom line it will save you much headache when tuning after a cam swap.

Most people around here are running a 3.73 or 3.42 gear. Performance is around the same with the 3.42 probably getting slightly better mileage. I personally like the 3.42 gear and will go to it sooner or later.

Re: l03 engine, l31 cam?
 

ive read on this forum that 305 vortec heads aren't very good and to use milled 350 vortec heads.any comments?

Re: l03 engine, l31 cam?
 

They do not know what they are talking about.;)

Re: l03 engine, l31 cam?
 

if gas mileage is such a concern, then leave it alone, of course a bigger cam/heads will suck more gas!!!