i am going to build up my stock 305 in my 85 IROC and was wanting some suggestions for what main priorities should be

i can spend about 2K on the buidup and plan on doing the following
headers and exhaust
a hydrollic roller cam
rockers
intake
port and polish heads
carburator
chip (mainly for rev limiter)

any suggestions on what to do first and what products to use

i currently have the all stock L69 motor and a t-5 tranny, 3.73 open rear

 

is your block able to accept a hydrolic roller? if i wanted a rev limiter i'd buy a rev limiter or a msd box with the rev limiter and you can always change the pills to suit you.
i know money is usually the limiting factor but i'd look at aftermarket heads and if i could get rid of the ecm controls i would.

 

I'll agree and disagree with Ed here.

Agree: An '85 block will not have a factory roller cam. Converting to roller lifters will be very expensive, and not yield significant benefit. You'd be better off getting an inexpensive flat-tappet cam & lifter set, and spending the money you save on better heads.

Disagree: There's nothing wrong with the computer-controlled setup for a street car. For best gas mileage, it can't be beat, and it'll hold its own performance-wise. Why a rev limiter is important to you, I don't quite understand, but a better coil and possibly module would be required to support higher RPMs.

I would modify your list as follows:
headers and exhaust [for '86-'91 single-cat TPI]
a hydrollic roller cam [make that a computer-compatible flat-tappet cam & lifter set]
rockers [roller-tip like Comp Magnum, or full roller Comps or GM's]
intake [not Performer, but Action + or GMPP would be good choices]
port and polish heads [or, port & polish World Products S/R Torquer 305 heads]
carburator [tuning all that's required]
chip (mainly for rev limiter) [coil & module upgrades, perhaps Crane/MSD/Holley add-on box]

Prices:
Exhaust - $700 for headers, cat, and cat-back.
Heads - ~$650 unassembled, plus $40 for porting kit.
Cam, lifters & timing set - $180
Rockers - ~$120-$200
Intake - $140-$175
Carb improvements - $30
Ignition - $150-$300
Gaskets - $50-$75

If you port your stock heads, you're well within your budget (stock heads will need new valve springs, and screw-in studs are a good idea as well). Roller cam & carb (and distributor) will put you over without the heads.

 

I'd suggest any kind of mods that can be transfered over to a 350 block, because if later you really want power, theres no point in having to change things twice, if however you're happy with a hottet up 305, the id follow five7kid's advice. If you want a 350 later, then just stick to your factory heads and have them ported. Other then that, id just get what the others have advised you to get.

Always remember, when buidling a 305, think about how long its gonna stay in your engine, if your just gonna throw in a 350 in the near future, then avoid the 305 only mods (ie, 305 heads and the like).

 

thanks for the advice

would a roller cam really be that expensive to convert to?

the rev limiter is because the stock one cuts out at 5500 rpm and i know that my motor has power past that

i plan on going to a 350 in the future and thats why i dont really want to get heads

anyone else have anything that they want to add

 

Your "stock rev limiter" is also known as "weak ignition and weak valve springs".

The stock setup doesn't have a real "rev limiter". It doesn't have any power past 5500 RPMs, either.

Roller lifter conversion really is that expensive. Quick look at Jegs catalog shows $380 for Crane retrofit hydraulic roller lifters ('87-later are $170), $300 for a Crane retrofit hydraulic roller cam ('87-later are $260). You will also need new push rods and a cam button. Oh, that cam isn't advertised as one of their computer-compatible cams, either.

Your T5 will last a lot longer behind a healthy 305 than it will behind a 350.

 

I gotta agree with five7 that the weak ignition is really what is holding back your RPM's. You will benefit from a new module and coil.

For intake manifold, I recommend Weiand Stealth (sorry don't have a part # off hand)

And it's a good idea to port your stock 416 heads over buying a set of World's. Then when you get the 350 down the line, you can invest into a set of good heads.

If you're gonna get a 350, look into a 87-95 block.

 

five7kid thanks for the info on the ignition, i thought that it was a rev limiter because it kicks out right at 5500 rpm

one of the reasons that im not doing a 350 swap is because i cant afford a tranny swap at the same time

what kind of rpm's can iexpect out of this motor if built correctly?


thanks for the info so far

 

I have power to 6000, and have rev'd it to 6300 on numerous occasions.

Stock, 143k miles lower end at the time of the mods.

Before the mods, mine would fall over at 5200 RPMs. Every time.

 

I really suggest getting yourself a long block 350 (the whole motor), from an auto parts store. Either that, or shop around the local want ads.

You can expect to pay about $1,200 bucks for this.

Now, depending on the tools that you have, I say get yourself an engine lift. You can get one at Costco or PriceClub for $170 bucks, a 4-ton engine hoist. That's all you need... I'm sure you have all the other tools. Pull the motor and tranny at the same time. It's actually VERY easy, just somewhat time consuming.

So so far you've spent.. we'll say about $1,400 bucks.

you still have $600 bucks.

buy yourself a better camshaft for your motor (if it didn't already come with one) for about $150 bucks we'll say.. that's pushing it.. but better to be realistic.

So now we have $450 bucks..

you still want headers right? GO get yourself a JC Whitney catalog.... order the "FlowTECH" headers over the phone, and have them special order the "Y-PIPE"

if you want to keep the air inlets on the manifolds... then ask them to special order that too..

FlowTECH is owned by Holley, and is their budget line performance exhasut manifolds.


You'll get the Headers and Y-pipe SHIPPED to your house, for about $198 dollars. I know this because I did the very same thing for my LU5 1982 TransAm.

So... now you only have $250 bucks left.....

well... how about maybe a new carburetor... I assume you still have the computer, so why not either upgrade the one you already have, or buy a new compatible carburetor.. that'll cost you about $190 dollars.

You still have 60 bucks gas money left.


By the way, the flowtech header kit comes with everything you need.. new gaskets, bolts, and even the kit you'll need to replace your y-pipe and attach the new y-pipe to your old pipes.



Anyway... your engine will probably be putting out around 275 horsepower, and 300 pounds of torque... that's a pretty average estimate... and that's assuming you get the average heads with the 1.9 intake and 1.55 exhaust.

That'll put you squarely in the low 14s


With all that you plan on doing to your 305... you're likely to only run low 15s.

Don't waste your money on modifications like MSD boxes.. or roller cams.. or crap like that..

in all honesty... those modifications, higher output coils, roller cams.. etc... ONLY help the performance of a motor in the upper RPM. There is no reason why a small block chevy in standard for could possibly need an MSD box...

As long as your spark plugs are not fouled, and your wires are good... and the distributor is tuned properly.. then you're getting the most from your ignition system.

The ONLY way that a high output ignition system would help would be... well... in higher RPM motors... the stock coil usually can not put out as much voltage as is needed at that high of an RPM.. basically.. say your SBC had a 6,500 rpms... above 6,000 rpms.. the ignition coil has problems keeping the voltage up to it's maximum as the RPMS increase... basically... the coil doesn't have enough time to charge up for the next burst of energy that it has to give out to the plugs...


your motor doesn't, and SHOULDN'T go above 5,500 rpms for any reason, because it simply doesn't put out any more power above those rpms in the current fashion that your motor is built up. In addition, it's not WORTH it for you to build up this motor in that respect either because it wouldn't be cost effective.

so.. long story short... don't buy a high performance ignition system.


Stick with the basics... do a 350 swap unless you want the 305 for sentimental value.

Todd

 

ta82
thanks for your opinion but going to a 350 isnt what i want to do right now, i dont have the money to get a new tranny and im kinda concerned that the t-5 will die with the torque of the 350, especially with the way that i drive
but thanks for the input



five7kid
would the msd 6AL module be a good system to get for the motor that i want to build

the other thing that i was wondering was what intake you recomend, the stealth or a GMPP ZZ4 intake

 

I've never heard of anyone who was disappointed with the MSD. Used MSD distributors, yes, but not their boxes. I've been impressed with the Crane HI-6 I have on the '57, but that isn't CC. Also, I haven't had any problems with the Accel module/coil I have on the Camaro.

The Stealth isn't q-jet or EGR. I found my GMPP as a ZZ3 take-off (identical to ZZ4), I've heard of others who have done the same. It's a nice little manifold. Check the classifieds on this board, or post your own parts-wanted ad. You'll probably find one for much less than what a new one will cost you from the dealer.

I think one of the worst wastes of money is an aftermarket, non-CC carb. There is absolutely no reason why the CC carb won't perform if the other parts are chosen correctly. You'll pay a little more for a computer-compatible cam, but that's a lot less than a new carb and distributor will cost you. I suppose that's just my little bias, though.

 

You guys have it all wrong! If he is gonna keep the 305 then just go to the following address,listen and learn!
http://www.goingfaster.com/spo/325_h...chevrolet.html

 

Id get the 350 TPI aluminum Vette heads also known as the zz3/zz4 heads... they are 58cc which are the same as a 305's heads..... they flow some un real numbers with a good port job, and they will switch over to the 350 you eventually get if you ever do!

 

*****, I think you need to listen yourself, and learn about the real world. RB pretty much listed the reasons your reasoning is wrong-thinking in the other post where you said the same thing (I guess you said the same thing - moderator edited out most of what you said).

sloth, The Vette heads are aluminum, which means a 58cc chamber has the same effective compression on a 350 that a 64cc cast iron head has. To use them effectively on a 305, you'd have to shave about 4-6 cc off them. So much for switching them over to a 350 later on. Oh, they don't flow all that great, either (okay, just not unreal).

 

five7kid
why is it that you say to not use there boxes, i thought that there ignition stuff was some of the best?

if i wanted to get this thing to redline at say 6500-7000 what else would i have to do besides a good cam, intake, exhaust, and ignition

if the aluminum heads arent very good for this app. could you get 54cc cast heads ( not to informed on heads and tryin to get info)

just trying to figure what i should be looking for

another thing whrere is the best place to buy all of this stuff at

thanks

 

No they don't. The World's unported S/R's outflow L98 ported heads. The World's also have more meat for porting, so the L98's will never catch up. Also I see these L98 Aluminum heads going for rediculous prices just because they're off of a Vette.

 

I didn't say that. I just said the module and coil were adequate for me. Many people have said you don't need the MSD-type stuff on mild engines, but like I said, I haven't heard anyone who had one complain about it.

Valve springs. When you get into that territory, the rockers had better be good parts, too. Also, stock rod bolts aren't going to last long if that is where you go all the time. I'd suggest you keep your redline at about 6000 RPMs. Beyond that, you're talking a lot of beefing up, and again, doing that to a 305 starts to become a money pit.

For a 305, you want 58cc cast iron heads. iroc22 and I both run the World S/R 305 Torquers. A little porting is really necessary to get them to run to their potential.

I picked up the heads and a bunch of other stuff from Competition Products (www.competitionproducts.com). At least early last year, their prices beat anything else I could find. Summit and Jegs both think I'm a loyal customer, though.

That's why we hang around here.

 

Ok I found the info on the Stealth I was looking for.

PN#8000
50 state legal
Front height 3.75", rear 4.63" (Should fit with the stock element)
700-6000rpm band
EGR provision
Spread and Square bore mounting flange
Will work with Q-jet

 

five7kid

i tried to locate those heads on several different sites but was unsuccesful, if i can find them for theright price i might get a set of them
i was looking in my edelbrock catalog and they have a lot of 52cc heads would this be to small creating a high compression ratio


iroc22

thanks for the info on the stealth manifold it looks like it would work great with the setup that i want to do

 

if i wanted to get rid of all of the egr and AIR eqiupment would i have to change anything else ie carb, computer stuff like that

 

The AIR equipment is no problem. But the EGR will throw a code I'm sure.

 

I got my heads from Competition Products (www.competitionproducts.com). They had the best prices at the time, I believe they've gone up a little but still the best.

You may have to call them and talk to a real live person. A lot of outfits don't list them directly, or only list them as assembled.