Hi All-

Having an all-original 1984 Recaro 5-speed L69, I wanted to pull the engine out and overhaul the engine. Knowing full well that it may be cheaper to just drop in a 350, I have a strong desire to keep the original engine block and q-jet carb.

I already replaced the stock exhaust system with a Magnaflow cat and cat back system.

What are my performance/appearance goals?
1) 290 hp/300+ torque (www.hioutput.com), not too crazy but making the 3rd gen more respectable on the street...
2) Keep existing T-5 and 3.73 stock rear, until operationally unfeaseable
3) Keep existing stock ram induction intake hood.

Understand that the cylinder heads should be around the 56-59cc range to keep the compression at a healthy level, which cylinder heads should work best? I've heard Vortec heads, ZZ4 heads, world torker, AFR... many options, but what WORKS best for a 305?

Exhaust headers? Since I have a T-5 should I concentrate on Hooker 2210 long tubes or something else?

Intake Manifold? Edlebrock performer? Keep stock? I want to keep the Q-jet and I do not want to have to need a new hood to make it all fit either. Which is the best option? Is it really worth replacing anyway?

Camshaft? Seems like the Comp Cams Magnum/Drag Racing, 292H Street/Strip Special would work..Any other options?

From what I understand the pistons on the L69 are adequate but the connecting rods are not as stout as the 350 connecting rods, so should any 350 SBC connecting rods be compatible?

From my somewhat limited experience with modifications, I have learned that there are ALWAYS unintended consequences of modifying parts from its original stock form. What caveats and problems have you experienced with regard to 305 L69 overhauls?

Thanks

Chuck

 

Heads - if you use Vortec heads you are going to need a different intake manifold. Since you have an L69 you have the 416 casting heads which are very good factory heads. It would be cheaper just to clean them up (mild port/polish) and resize the intake valves to 1.94. Trickflow makes a dedicated 305 head but you are looking at about $1000 but then you won't have matching number heads - originality seems to be your goal.

Headers - I'm a huge fan of Dyno Don's. They fit perfectly!!!

Intake - There is very little difference between the Edelbrock Performer and your stock piece. People say you get an o-so-slight more power with the Edelbrock but for originalities sake you could just get your factory aluminum intake blasted and it will look just like a brand new unit. Remember, you are limited to no bigger than an Edelbrock Performer intake. The RPM will NOT fit with your factory air cleaner.

Cam - I'm not the biggest expert on cams but I do know that the 292H is WAY to big for your daily 305 with a CCC. I personally have a Comp XE262 and am very happy with it. The site you listed uses an XE268 which should work to but you have to make sure your springs are up for it. You also have to take into consideration that your computer may not like the XE262 or let alone the XE268 (mine didn't).

Rods - the rods in your 305 are the same as a 350. I assume you will be replacing the pistons so you might as well buy some new rods. They aren't THAT expensive and at least you will know that you have a good quality rod. Rods bolts usually brake way before the rod themselves. Make sure you use ARP bolts for them.

My problems - MY L69 build was fun but a nightmare. I originally had a problem with the carb getting horrible gas mileage with a 327 Vette cam from the previous owner. Off came the cam, and what the hell, let's pull the motor too type of thing. Looooong story short I had to replace the entire CCC system with a standard quadrajet (bad computer), I blew the tranny in the first 5 miles, and I had massive overheating issues due to some really crappy fans. All of this in more in the link in my signature. It might be a good eye opener :-)

 

So you want to change heads, intake, rods, cam, ect...why reuse the 305? Its not an L69 anymore. Pull it & put under a tarp. Spend your money towards an engine that'll already have a roller cam set up like a vortec.

 

I agree, totally understand keeping things as stock as possible, but your plan doesn't make a lot of sense.
I think you really just want to put some headers and exhaust and leave it there. Maybe some light porting on the stock heads and a slightly bigger cam.
Oh, and the stock intake isn't "ram air" it's as bad an intake as any other of the era, make your own true ram air or a better cold air induction.

 

I disagree with your last statement, Stealth. The functional hoods on the early Z28s and firebirds were VERY effective. They were even better for flooding out an engine :-)

 

Cool thread..
i have also a l69 and only little mod with the cam yet.
I am thinking about porting and polishing too,.. You can find several comments that it is cheaper to port than to replace.

Have you already done something until now?
My next step will be an replacement of the complete stock exhaust.. At the moment i only have a flowmaster 80 underneath.. The rest of the system is very restrective as a lot of ppl. will tell you here.

Ahh.. Before i forget it:
I have also an edelbrock performer 2101 (and no more EGR or AC)

 

No, I have not done any engine modifications yet... I changed my priorities...Right now I am concentrating my $ and time to the suspension.

I do still have a desire to "warm" up the L69 however, it will just be another year or so...

From the information that I have gathered, it is really hard to say with any degree of certainty what performance "numbers" you can expect by just doing the intake and headers...

For example WRT aftermarket intake manifolds, I have heard "You cant get jack anything out of a new intake, don't waste your money" to "You should expect to see a 20-25 hp gain"... As for headers, i have heard the same....

So, I am going to put my money on upgrading my stock bushings, shocks,struts,springs, and whatever else can help with the rigidity of the chassis then I will address the L69.

I am also concerned if I do build up the L69 to the point of the fabled "300"+ hp that some refer to....that I will blow my original T-5 .......then I will be dropping 2-3 large on a T-56....Not a bad upgrade mind you, but just not having 2-3 large burning a hole in my pocket

So my plan for the engine, when the time comes...

1) Get the car on a dyno, just to see where the numbers are now... I am currently running a stock motor with original exhaust manifold and a magnaflow cat and cat back.


2) Hooker 2055 shortys
3) Performer Intake

Get on the Dyno again, and document the findings... If I am at 240 hp and 280 TQ at that point, I will stop for the sake of too much pressure/stress on the T-5.

If the numbers are 220 or less for hp and 260 TQ or less then:

1) add a mild cam

2) port and bore the cylinder heads form 1.84/1.5 to 1.94/1.6 (or just leave it at 1.5)


Happy New Year!

 

Oh, to answer your question about porting and polishing.. I came across somebody who is willing to sell ported and polished 416 heads with a 1.94 bore for $225 each plus shipping... So for just over $500 you can get new heads with new rockers, springs, etc. with better intake flow

I wonder if at the end of the day, that you're better off buying these than porting/polishing and replacing rockers, rollers, springs, etc ...plus the boring out to 1.94 at some machine shop.

 

here is the ebay link

http://www.ebay.com/itm/170358005738...84.m1423.l2649

 

the regular 1.84 416 head is listed, but I asked him about the bore to 1.94 and he quoted me $225 each

 

Here is wintertime and my car is sitting in the garage.
I will do a dyno in spring.
Ive got a pre tune dyno but overhauled and with the mild cam
And ill do a dyno in spring with intake manifold and remanufactured&finetuned cc quadrajet. Maybe I swap the cam if i do a port&polish to the suggested XE262
I'll date in this thread if i do so