I am getting my friends 1991 Chevy Camaro RS Convertible in the next week or so. I am planning on keeping the 305 in it...at least for now. This is kinda of my plan here: http://www.goingfaster.com/spo/325_h...chevrolet.html
I plan to get some Vortec heads. I was originally planning on getting these: http://www.summitracing.com/parts/NAL-12558060/
However, I do intend to run some nitrous...probably a two stage at some point. I came across these...that have a .520 valve lift...that would be better for a nitrous cam: http://www.summitracing.com/parts/SUM-151124/
Now the question is which heads for a motor that i plan to use nitrous on? What effect will the 67cc combustion chambers have on the 305? If I get the heads with the .520 valve lift...I will probably use a nitrous cam. But which one? http://www.jegs.com/p/Comp-Cams/Comp...46630/10002/-1 I know that I will have to get an intake to work with the vortec heads, and carb, and distributor, and blah, blah, blah. I just want to know about the performance parts. Sorry this is so long...just have a lot of questions in my head. Thanks for any help you can give.

Cam

 

You do understand no carb is emissions legal in any of the 50 United States.

Getting better lift heads is a good idea. But, I'd assume getting better valve springs than what comes with those heads. I'd also lean toward sdparts.com heads vs. these.

As important as the heads is the piston type. Stock cast can usually take a properly set-up 150 shot with no problems. Hypereutectic shouldn't be sprayed at all. Forged will live the best but are an expensive add-on to a 305.

I can't help you much there. But, the decision will probably be based on how much street driving vs. track time you expect to do.

Don't cheap out anywhere. A good ignition is vital with nitrous. The MSD Digital 6 box has ignition retard built into it. I hope you're not thinking about an Edelbrock carb.

 

five7kid and I will never agree about the merits of Edelbrock's carbs, but he's correct that they're illegal on your '91. As for heads, your stock heads are 55cc, and your real compression ratio is 8.8:1. If you use 67cc heads, and FelPro steel shim head gaskets, you're down below 7.6:1. That would suck, even with your stock cam and a supercharger. For heads, your best choice is the Trick Flow 175cc heads, available only through Summit Racing. They're designed for 305s, have 56cc chambers, will accept plenty of lift, and are 50 pounds lighter than iron heads.
Why are you looking at non-roller cams? Not wise. order something with 218/230 duration at .050", .495/.510" lift, and then go with 1.6:1 rockers for .528/.544" lift. For a 305, a 114 lobe sep will be better than a 113, just slightly. This will want a 2500-stall converter, but will pull well to 6200 rpm. Combine with 3.73:1 gears, and 26"-O.D. drag radials.

 

I happen to live in a state...South Carolina...that doesn't give a rats *** about emissions. So I can pretty much do whatever it is that I want...no hood, carb, no cats!

I haven't looked at the sdparts.com heads...I will check them out.

Yea, probably not going to be doing any different pistons in the 305. Maybe later on when I change it to a 350,383, or 400.

I want it to be very streetable...that is why I want to do some nitrous on top of the other parts.

Not really thinking about an Edelbrock carb...but I have nothing against them. Maybe a Demon...or a Holley.

Cam

 

Can you give me the part number for the Trick Flow 175cc heads...it isn't listed when I put the car specs into Summit. I won't have any problems using a roller camshaft with the things that I am wanting to do? Can you post some cams that you recommend for your specs? I have a 2400-2600 stall converter for it...I think that is the stall I have. I don't know if I will change to the 3.73 gears or not...since I intend to use nitrous. And everything that you have listed here will work well with nitrous...say a 125-175 total shot?

Cam

 

Also, what would be the compression ratio with the 64cc vortec heads?

Cam

 

http://www.summitracing.com/parts/TFS-30300001/
for the cam, call 800-999-0853 and order part number 08-000-8, with a 3313 intake lobe, a 3315 exhaust lobe, on a 114 degree lobe separation.
One of my customers is running the exact build I suggested, and is running 12s in his daily driver Camaro, even up here at 4500' elevation. At lower elevation, you should see low 12s. I just called him, here's an update: With a 200 shot and a Jacobs Nitrous Mastermind, 3.73:1 gears, some 275/60R15 M/T drag radials, and a 3000 stall, with the jacobs set to give you 50% of that 200 shot at 3000 rpm, and progressively increasing the flow up to 100% at 6000 rpm, you should see high elevens, since he's now running low 12s with this revised combination. Of course, he has forged pistons and his plasma-moly rings are gapped for nitrous.

 

I got to be honest...I didn't really want to spend $1000 on heads. I was trying to find something that would perform well for less. I will have to think about the heads some more. And your customer is still running a 305, right? I have a B&M Holeshot 2400 converter...the stall is 2300-2500 rpm. What effect would my converter have on the setup that you are recommending?

Cam

 

He's running the 305 block from one of my personal LO3s. Your converter will drive well with the cam I suggested, I've driven that converter myself, in 2 different Camaros. But at the dragstrip, the 3000 stall would be worth another couple of tenths. Not a big deal. There are a lot of heads that can be bolted to a 305 block, and some of them will feel pretty strong, but these are the best. My second choice, for less money, is milled Vortec 350 heads with my stage 1 intake and stage 2 exhaust options. I've described these before, but long story short, I do no porting to the intake ports, but find another 12 cfm from better valves, still 1.94", but with undercut stems, and 30-degree back-cuts. The exhaust side gets similar valves, but 1.60", with the seats cut to match, and a 5-angle valve job, 15/30/45/60/75 degree angles, the 75 done as deep as possible, and until the 60 is about .050"-.055" wide. Then taper the exhaust guides, and polish the exhaust ports. But by the time you do all that, you're so close to the price of the TFS heads, and they give you the weight savings of being aluminum, plus they save you the price of a Vortec-specific intake manifold. In the end, the TFS heads are the better deal for a 305-based engine.

 

wow atilla, it seems like you really know your stuff
any more words about the TrickFlow heads? any mods to improve them even more or are these simply the 'best' (i know, this is subjective, but still..) 305 heads out of the box?
thanks in advance

 

Doesn't matter, because it's not state law, it's Federal law.

 

What I am saying is that I have no inspection or anything like that. I can run whatever I want because no one is going to check the car. That is unless I move to another state at some point.

Cam

 

Like I said...I will have to think about the TFS heads a lil bit. How would they do on a 350, 383, or a 400. I plan to swap out the 305 at some point. What intake manifold would you recommend for the TFS heads?

Cam

 

And how would I use this cam that you have recommended here when the TFS can only take a max of .480? Or do I have that wrong? And this combination is going to put me over 325fwhp...on the motor alone?

Cam

 

well, i don't think you can really bolt these to a 350, at least not without some modification!?

btw, those TrickFlow heads are also available with .540 and .600 lift:
http://www.summitracing.com/parts/TFS-30300006/
http://www.summitracing.com/parts/TFS-30300007

edit: forgot to add, i did some research about vortec vs the TFS Super 23. i don't know how he did it, but Fast355 made his 059 flow even better than those TFS. here are two links for this interesting comparison:
TFS Super 23 flow
Fast355 ported 059 vortecs (scroll down for flow table)
i dont know what his 059 flowed at 0.600, but frankly, how much time do your valves spend at .600 lift..

 

These are excellent just as they arrive. This set was so good I didn't need to do any polishing of the exhaust ports, so I just cleaned them, verified they'd accept the lift, and installed them. I'm certain that they can be ported, but they're already better than the Vortec heads, especially on the exhaust side.

 

If you don't damage them, you should be able to sell them for around $700 when the time comes, and that will get you a new pair of Patriot Freedom 185cc heads with 2.02/1.60" valves. That's the smart approach. Those Patriots would be miserable on a 305, and you could only run .450" valve lift becaust of intake-valve-to-bore issues.

 

Those heads are offered with several choices of valve springs, I just linked you to the first of several listings. For this listing, the springs are what limits the lift.

 

They bolt to a 350 just fine, and I myself have ported Vortecs to outflow these, but they're still iron, and they can't be flat-milled to less than 53cc, while these can be milled to 48cc.

 

as to the 325 flywheel horses, this combination is good for 365, about 40 more. But you'll be losing some to things like your power steering pump, and so on.

 

I don't really want to have to buy two sets of heads is what I was getting at. I was looking for something that would be okay on the 305 for now...and be good on a 350,383, or 400 later. I don't particularly want to get into trying to sell a set of heads that only perform well on a 305. Most people aren't really looking to build up a 305...let alone spend a lot of money on one.

Cam

 

Why would I want to my heads flat-milled to 53cc...or less than that?

Cam

 

So keeping power steering and such...maybe in the 350ish fwhp neighborhood?

Cam

 

Gotcha. As you go up in lift...the price goes up a little bit each time too.

Cam

 

Sorry, no such heads exist.

 

Because stock LO3 and LB9 heads are 55cc, and that gives you a true compression ratio of 8.8:1 with the GM steelshim 305 head gaskets. You'd like to get to 9.5:1 with iron heads, and it is possible, but the options aren't worthwhile. With aluminum, you'd like to get over 10:1, but even with the TFS heads milled to 48cc, you're not going to get there.
Your best bet is a 100-hp shot of nitrous on the 305, and go find a 350 or 400 block instead of buying heads for the 305.

 

I am very interested in Fast355's build. I am going to look over it more intently. Thanks.

Cam

 

not a problem on the link killa66. you're welcome

hmm, not even with flat top pistons and a decked block?
btw, do you know what thickness the stock GM steelshim is?

 

With flat-tops you can get there, but if you're going to go there, you may as well do a 350.
As for the gaskets, even these TFS require a larger-bore head gasket, and since stock 305s have the pistons far enough in the hole, the FelPros are the best choice. Thinnest, most common, and easiest to use because of that rubber coating.

 

So I can't do something, like the link that I posted, to put me in the neighborhood of 325fwhp...and then switch it all to a 350, 383, or a 400 and end up with high 300ish - low 400ish fwhp?

Cam

 

If you build a 365 hp 305, then swap the heads, cam and intake to a 350, you're still at 365 hp, you just get it at a lower rpm. You can build a 400 HP 350 with Vortec heads, but put those parts to your 305, it'll be miserable. Besides, the Vortec heads are a poor choice for nitrous, because of the poor exhaust port flow.
Stop trying to hop up the 305 for now, and start putting that money into your big engine. Then you can get even better aluminum heads for less money.

 

I guess I may wait and think about the engine a little bit more...and maybe see if I can find a 350, 383, or a 400. I guess I can focus more on the rear axle, suspension, and rims/tires for now. I appreciate all the recommendations.

Cam

 

Does the 305 in a 1991 Camaro have a roller cam in it from the factory?

Cam

 

yes, it sure does. It's a tiny little thing, too. 178/194 duration, .350/.385 lift, IIRC. The "RamJet 350" / marine cam is a good cheap upgrade. No point going any bigger with those swirl-port heads.

 

What are the specs on the comp cam that you recommended, 08-000-8?

Cam

 

the 08 prefix means '87-up SBC, the 000 means custom specs, and the -8 suffix means roller. Because of the 000, you have to specify which lobes and what lobe separation angle. For the lobes I gave a few days ago, that's 218/230 duration at .050", .495/.510 lift with 1.50:1 rockers, and a 114-degree lobe separation. This is the grind I installed in my customer's nitrous-ed, TFS 175-headed 305 buildup. It passes emissions testing just fine.

 

What cam would you recommend for one of the sdparts upgraded, vortec roller head kits? http://www.sdparts.com/catalog/engin...rHeadKits.aspx I know that you don't recommend the vortec heads for the 305, but if I decide to go with them anyways, what would be a good cam for up to a .575" hydraulic roller cam? And would you do the Edelbrock Performer or the Edelbrock Performer RPM Air Gap intake?

Cam

 

I'd place the same order except lobe 3303 for the intakes. The performer fits better, but unless you use the RPM, it won't flow as well as the heads. On the Superflow 1020, bolting on a regular Performer always drops the flow numbers to right at 215 cfm. I haven't seen this with the RPM.

 

Hi Guys,

I´m quite new to the forum, and also to the camaro world. I´ve felt in love with the third generation when i did high school in the US (I Live in Brazil), and now, after several years, i could buy one down here.
It is a 1991 RS t-top 305 TPI (it was a TBI, that i recently converted.. Ufa..), and now, i want to throw some extra horses. I´ve seen your thread and since i was thinking about this same setup, i´ve decided to get some advices.

These is what i was thinking:
http://www.summitracing.com/parts/CCA-08-304-8/
http://www.summitracing.com/parts/TFS-30300007/
http://www.summitracing.com/parts/TFS-31400511/

* I might stroke it to 335 as well

My concerns are:
Will i need a custom chip? (I have the original 730 + original 90-92 305 tpi + hypertech)
Will the iddle be like the original setup, clean, or it will be like the other camaros i´ve seen around, where the iddle is kind os square ad it only cleans up when you hit the gas?
What else should be interesting, besides nitro?

thanks for the thread.

 

1. You will need a custom chip because of the camshaft
2. Your idle will be noticeably different than stock, but that's what we like.
3. What about changing your intake setup to an HSR, so your engine can breathe more?

 

Thanks for the answers.

What about injectors? What size should i be installing with all these? (mine is the original 19lbs)

Will the car run, and perform quite well, even without the custom chip? Who in the market can provide this kind of service ( a good reliable one)?

Thanks again

 

There's no sense stroking it to a 335, it costs more than just doing a 350, it has no advantages over a 350, and if you do the 350, you can keep driving the 305 until the 350 is ready.

 

A 91 RS with a 305 did not come with 19-pound injectors. The TPI cars used 8 of the 19-pounders, and TBI means 2 injectors, so you can see there's no way they're only 19 pounders. But the Holley 670-cfm TB, which is basically the same size as the TB that GM installed on the 454ss, can hold injectors that'll support 150 horses each. You'll need to run a wet nitrous system, though there probably isn't a dry nitrous system for your car anyway. NOS does offer a system for your car. With any of the cams suggested, you will need a custom tune to even drive it at all. Depending on your choices, it might not even stay idling without the custom tune. I pay my local chassis dyno shop for all my tuning work, but there are many companies that will do a mail-order chip that "should be very close" but often isn't. If you haven't bought any speed parts yet, call TPiS, and they'll do you a package that includes a cam and a chip among other things. Then you'll know it's good to go.

 

My car is no longer a TBI. It is a RS/Z28 (i've installed instake,plennum, runners, chip, everything like the 5.0 Z28)
Do you think this setup, the one i jamed, will work nice with my 305?
What about the injector size, should i get bigger ones?
What do you think about stroking it to 335? (U$700)

Cheers

 

again, stroking it to a 335 is more expensive and more inconvenient than just building a 350. Keep driving the 305 while you build a 350. A 335 has NO advantages over a 350.

 

Thanks again. I was just asking because it seems cheaper to buy the stroker, and it is also easier to bring it back to Brazil. I know that a 350 is a better engine.
In terms of HP and torque, how far behind would a 335 be compared to a 35?

I've contacted TPIS and faschip, and both said that they can built it. The only problem is sending the chip back and fourth in order to make it 100%.

Thanks

 

What intake would you recommend if I were using 305 Vortec heads (059)? I am contemplating doing the 059 heads, with a LT4 cam...if I can find the 059 heads that is.

Cam

 

You're at more of a disadvantage than it would seem. The small bore shrouds the valves, even on the TFS 175 heads. Plus the available pistons are not forged, so you have to be more cautious with the nitrous. And even so, if you're closer to sea level, you'd be better off with Edelbrock E-Tec heads to keep the compression ratio sensible with the Keith Black pistons. You'll need to order a stroker kit from a company who can balance it for you before shipping it to you, as engine balancing outside the U.S. is risky at best, no telling what equipment and operator skill you might be stuck with elsewhere. I mean no disrespect to other people's intelligence, but the fact is that the best engine rebuilding resources are here.

 

That depends on if you plan on keeping the 1.84/1.50" valves, or not. And will you be doing any porting? Even if you go to 1.94" intake valves the best wayu, those heads still won't come close to the 350 Vortec heads, because those did NOT get the same improvement to the short turn radius in the intake ports. They're no better than LB9 heads, but they do require a Vortec intake. That's just a way to spend more money.

 

Thanks again.
I´m not at sea level. I´m 2493 feet above it. I saw that the Edelbrock E-Tec are only available from 64cc. Wont this affect my compression rate? My 305 is 56cc or 58cc right?
Powerhouse can deliver the same stroker but forged, and balanced.
My first step will be replacing camshaft and heads. That´s where i cannot decide what to do. I thought that TFS + CCA-08-304-8 would be nice, but thereare too many optiond out there. Please, it would be nice to hear your personal opinion, on what cam and heads to go with.
I don't want my car to have 600hp.. I just want a mild good hp and torque.. If i get around 350, without the nitrous, it will be enough.

Cheers