Experts, I need your opinion!!!!

I have just recently hit 138k miles on a 1987 IROC-Z28 all stock except for the new cat exhaust. I currently in the process of Blueprinting a rebuild process. I have read a lot of your current set ups and have came up with this one for mine:


-BBK 52 mm TB
-Ported Plenum
-Large Runners(AS&M)
-Big Mouth Intake
-ZZ-9 Cam(Probably go get a custom one done from bulletcams.com for less just can't let myself buy a street cam for $375)
-1.5rr
-I already have put a 3"in cat exhaust system (custom job-Borla setup for less)
-1 3/4 coated headers
-spark plug wires that has a less resistance that the stock ones
-spark plugs

-Ported Stock Heads

Okay, here are the questions, can I get away with the stock cast heads and zz-9 cam? What do you think this setup will give me in hp? And what are some recommendations that you have so I can get maximum horsepower and not have to sell all my shirts to raise money? And what are some of your setups that may be an L98 with stock heads that works well for you?

Car Gods let me have it!!!!


:hail:

 

Why spend all that money and then port the stock heads? Either get some Vortec's or some Iron Eagles.

 

I was thinking about that I probably would go with some Vortec Heads but I have done some research and that the Vortec Heads don't line up with the Baseplate. Do I need to buy a new baseplate from spdc or are there other alternatives to getting my stock baseplate to line up?

 

You would need a new baseplate from SDPC.

 

Okay, will do, I guess I will have to fork out the extra $350 to $400.

 

No need to spend extra cash, you already had an aftermarket baseplate listed in your original list (the big mouth). Just get the vortec tpi one instead.

PS-What does this post have to do with blueprinting??

 

I think he meant more of a "Blueprint" for his car. In other words a detail list of plans and mods. Not actually blueprinting as in rebuilding a motor.

Speaking of which the term blueprint is really a catch phrase for, "somebody took the time to measure and do proper machining to see that everything went together under specified tolerances. So when someone says there engine is balanced and blueprinted, it just means it was put together properly which one would hope all engine rebuilds are.

 

Just meant that I am trying to pick out the best combination, "blueprinting", that I can get for my planning to rebuild my motor. I just wanted to have everything figured out for now as far as what I wantbecause I don't plan to rebuild until winter, like December or January. So, as we all now money don't grow on trees around here. I chose this way so that I can slowly buy the major parts over the next 6-7 months and then by the time January hits I have just about everything in front of me so I can build it.

 

Oh, and another thing, I thought the Big Mouth Baseplate was around $430 from TPIs.

 

Keep in mind that with the SDPC baseplate, you will need to do some porting. From what I understand, they don't flow much better than stock, and you can't use aftermarket runners without a little massaging either.

....I'm sure it's worth it, but just be prepared.

 

TPIS big mouth is $425. soon i will be running a 358 cid engine with 5 angle valve job stock heads a custom ground cam, probly 1.6 rr's and the big mouth with ported plennum and runners. tes headers and the hooker cat back. i'll let you know how it goes. thats all i can afford to do

 

I would have to shell out $400 bucks for an intake manifold, that I'll have to do some porting to and message aftermarket runners. Not a good deal at all.

 

If you want the best bang for the buck, simply yes expect to do some porting. Main reason is that these manifolds are designed to be used with stock runners and gaskets if desired, so the openings themselves are matched to stock. Once you get past the opening its a whole different story though, they flow much better. So basically you need to port and gasket match your intake base to your aftermarket runners (if you have them) and gaskets.

 

So let me ask a question then, If I go with TPIs Big Mouth Intake Manifold which is ported for Large Runners and port matched to stock, do I still have to do some porting for maximum performance. Also, are you talking about porting for the runners or porting for the heads or both?

 

Just about everything can be ported for better performance, but the TPIS stuff flows pretty darn well.

 

From what I understand the TPIS unit is the Edelbrock unit with a bit of port matching done. How much I don't know, I have never been able to inspect one. So I would have to guess they port match to there runners. You also pay for that porting though with a higher base price. If you bought the base and runners from them you might be ok. Your stock plenum will still need some porting though.

I was refering mainly to the porting on the intake manifold, runners, and plenum. Of course your heads can be ported also but thats a whole different story.

 

I'll give them (TPIs) a call and see what they think, I'll let you know how it goes.

 

Ask them what the diameter of there porting is. Stock is about 1.44" or 38-39mm.

 

Just got off the phone with TPIs and the gentleman said that the bolt pattern of the Big Mouth does not line up with Iron Vortec Heads. I guess with all the stuff you would have have to do you might as well go with the SPDC baseplate instead. Sorry, omcrider, I just got your message after I made the call.

 

SDPC is the only after market base I am aware fo that will allow you to use Vortech heads. So if your going that route thats your only choice.

 

I was comparing my Edelbrock TPI manifold(1st year production) with the current TPIS manifold at Dyno Don's. The intake ports on my Edelbrock measured around 1.70" and so did the TPIS. They are both made by Edelbrock. Maybe TPIS has done porting in the past but this current manifold was just like my Edelbrock. Allen

 

Now with the SDPC baseplate, I am guessing that I will have to do some porting to support larger runners or do I just go with some stock size aftermarket hi-flo runners. I am not sure if I will see any horsepower gains going with a larger diameter runner. Obviously, the engine would be able to breath better but I don't want to buy them if they don't really add more horseses or add to the efficiency of the engine. This is a similar dilemma as going from stock 48mm TB to a 58 mm TB and your engine topping out at around 300 hp. Overkill that is what I would like to avoid here. I will pay to play but I just won't waste money.

 

1989gtatransam Thats interesting the Edelbrock I just purchased the inner passages are easily 1.70 but the port openings were stock size Are you sure the one you have hasn't been massaged.


STR8BALLIN22, Runners and intake go hand in hand, to do one without the other is a waste. If you could only do one I would have to say the base is the one to pick. Shop around ebay and these boards wait for a set of runners to pop up in the $150 dollar range and pick them up. Doesn't matter if there Edelbrock, or SLP, TPIS, or Acell there all better than stock and except for the TPIS are cast and can be ported out. Quite often you can find deals for the baseplate and runner combo used for what you might pay for just the base.

The throttle body is the last thing you should change on your intake and pretty much not necesary until you have head work done.

 

STR8BALLIN22 Also There are no stock size high flow aftermarket runners, all the aftermarket runners offer some improvement over stock. You may still want to port slightly or possibly do a mild siamese on the upper runner openings and plenum. I am of the believe that if your going to spend the money to go this route you might as well increase your gain slightly by doing some extra porting.

Don't forget to knock down the wall in your plenum behind the throttle body and open the plenum ports up also. Match everything to a set of gaskets. Doesn't do any good to port if your gasket is going to block your passageway.

One more note on these mods. As you may know the TPI system was designed for torque at low rpm's. Effectivly porting and increasing the airflow will change this powerband. Its not uncomon to gain 0 or possibly lose a few ft lbs doing this. You will feel alot more pull in the top end to make up for it with a gain in HP.

 

The SDPC intake has some pretty nice casting as is, except for the stupid injector bosses taking up alot of the port. I ground them down to a reasonable bump, and pretty much just had to touch a port here and there, but they really matched up well to the vortec heads. The runner diameter is larger than the stock runner, so I bought big mouth gaskets and used those, along with SLP runners, which I ported quite a bit at both the top and bottom. The other aftermarket runners are probably alot nicer than the SLP's, but I couldn't get myself to spend over 400 bucks for some stupid aluminum tubing. I port matched to big mouth gaskets at the plenum, but had to make some concessions on the bottom side, as the runners would have been too thin to seal properly, so i gasket matched up to about an 1/8 of an inch thickness on the runner for sealing. For the 300hp or so I'm shooting for, it was a major improvment over the stock stuff.

If you aren't looking to do alot of modifications, the SDPC intake with other aftermarket runners(not SLP) would suit you fine.

 

The last TPIS base I ordered was not ported. And yes, it has 3860 right on the bottom of it (Edelbrock part #)

 

No kidding, I did not know that TPIs took Edelbrock's #3860 and just did some mild porting. I guess the difference in price reflects the porting work that they did. With this setup I was thinking to go with the ZZ4 Cam, I was thinking ZZ-9 Cam but no way will I pay 300 for that especially when I can get the same cam custom made for less. Do you think that with the Vortec Heads, SDPC Baseplate, Aftermarket Runners by whomever, and the ZZ4 Cam is a good setup. What would be a better cam option if you have one? How much would a setup like this give in hp? And I understand that I might lose a little torque and I know we can't be both quick and fast!