350 TBI for my 91 RS. . .

this is the crate motor I plan on getting when I get back stateside

http://www.goautocenter.com/300hp_tpi_1987-89.htm

My choices for upgrades to this crate motor are the Edelbrock Performer Centerbolt Aluminum heads or the Trick Flow 23* Aluminum heads. Now the guy from the store emailed me and said that they're worth about 20-25 HP, but I of course that can't be varified.

So which ones would you upgrade to? They're both the same price, $800 installed.

 

Trick Flow 23* heads flow much more and will make more power than the Edelbrocks for sure.

 

The really bad thing about the Edelbrock heads is their casting. Once they're outta the box, their pretty much as good as they'e ever gonna get period-not enough material for future blending/porting. Even if you don't plan on it now, get a head that can grow a little with your future needs.

 

My vote is for the Trick Flow heads. I'm running them on a 355ci with an Edelbrock Air Gap manifold and Holley 670cfm vac. carb. They are good heads for the money. Their only downfall, the valve springs aren't that good. I had mine switched to Z-28 springs and no problems at all. Motor will rev to upwards of 6500rpm with no valve float at all.

 

I saw a web site a long time ago with the "z-28 springs," but I don't recall where that was. Can you point me in the right direction?

 

You may be referring to the SDPC ads you see in magazines which advertise LT1 Z28 springs as an upgrade for the L31 Vortec heads they sell....

 

Just go to your local machine shop and they can hook you up with the Z-28 springs. Their good to .525 lift and are extremely cheap. Most shops I've ever been in literally have these things already bagged up ready to go for around $50/pr heads, but I would recommend changing them once a year depending on your usage. Daily driver, definately once a year to make sure they're always ready to go as with a brkt car just for cheap reassurance.

 

My vote is for the Trick Flows as well. Very nice head for the price.

 

Once a year? Why would these springs needed to be changed out once a year? The cam that's in that 350 is not that huge, nor do I drag race, minus the street of course.

 

Because they are soft springs and even with a peanut cam it is amazing what a set of fresh springs will do to an engine. I kinda exagerated a little, but springs get weak and the power numbers in the engine go down alot.

 

Now, if I can only figure how all of that valve lash and rocker arm settings and torque specifications things work, I wouldn't have to pay someone to do it every year. I think I'll try to find some nice durable springs and some good 1.5 (possibly 1.6) roller rockers and attempt to learn all of that in a weekend when I get back.

Thanks for your help.

Semper Fi!

 

It's super simple to do, but like I said I kinda exagerated the fact. I have 2 years on my current springs in the heads I bracket race with that are long over due for a spring swap but its a new engine going in so I could care less what happens to these current heads. If it's a daily driver with no consistent racing I'd probably go 2 or 3 years at the most then seriously consider changing the springs. Along with the routine maintenance to keep the motor in tip top shape, valve springs are a disposable item as well especially when talking about a peanut cam since the pressure doesnt need to be as high they'll live longer. But given the extreme duty cycle these springs must endure and the critcal job these thiings have it's just cheap insurance to make sure they're up to the task. I've seen gains from .1-.15 on a small daily motor at the track with a spring swap only and on a buddies race engine he went from running 10.10-10.15 down to 9.80...it was that dramatic and they only had half a season on the springs bracket racing only. So take it for what it's worth.

Oh if and when you decide to change to a 1.6 rocker, buy an adjustable pushrod to check the length so you know you have the correct geometry. Another cheap idea that will pay back in the long run with longevity.

 

Well, I'm pretty sure the springs on there are good to .520, so I should be fine for a while. After that I'll probably just order replacements from Trick Flow.

I think I also might just go with 1.5RR's because if I go to 1.6 and change the pushrods it will supposedly void my warrenty.

But thanks for your help guys. You've convinced me to go with the Trick Flows.

Why do I get the sneaky suspension that there's an anti-Edelbrock movement brewing??

 

you wont have 2 change the push rods when switching to 1.6 ratio

 

I'm glad you've taken the time to check out Gunnies Motor for him so he you both know the geometry is 100% correct for his vavletrain. I'd a hated to see him just throw them in there and think they are good to go.

 

Hey Gunny - let me know how you make out with that engine. I am seriously planning on that SPECIFIC engine to replace the very worn out L98 in my 1987 IROC-Z, and would love to know how it fits/runs etc. I am gonna go with stock heads as this is a daily driver and reliability comes before performance (not to mention how much cheaper regular unleaded is than premium in this neck of the woods!) I talked to those guys as well, it's based on the 93-94 caprice engine, it's a GM crate engine with a TPI cam. That's the engine they put in the police interceptors! So let me know how you make out!

 

Not here, I vote Edelbrock I have a set of Performer RPM 64cc on my engine.
My Comp XE284, Victor Jr, & Holley 750DP run fine up to speed. hmmm - in fact it pulls pretty dang hard.

Ron

 

Not really a anit-edelbrock, these are a good set of heads. All I was saying is that they're really not a head that can grow with your ambitions since they cannot be worked over to be any better than what they come out of the box. These are for you average joe backyard builder than wants a great running street machine.
Now take a set of Dart pro 1's, Brodix track 1 or 2's, AFR's and they are naturally a great head outta the box...but they also have thicker casting so you can massage them iinto an even better flowing head for a bigger badder motor when you reach that poiint.

 

Well, I won't be able to tell you how it is until the spring time. Let's just say at the moment, I'm at a place that doesn't allow me to work on my car. . . . or eat good food, or sleep in a decent bed, or go where I want. . . But it's all worth it in the end.:rockon:

 

Well they emailed me back today about the part number for those heads. It's TFS-30400001

Now I'm confused, because these heads are pre-87 heads going on a 93 block???? Now how does that work? Also, doesn't this change things about self-alinging rocker arms and fitment with my intake manifold and not to mention valvle covers (although this part might be a blessing)?

Here's a link to TrickFlow's website. The heads are at the top of the list.

http://www.trickflow.com/product/prfeature_index.htm

 

changing heads wouldn't make it reguire premium... especially if you go with aluminum heads which stay a lot cooler then cast iron.. you can actually have a higher compression ratio (smaller cc chambers) and still run the same octane then if you had the larger chambered iron heads

 

I ran the tf on my L98 and LT4 cam and ran 87 octane perfectly. No need for premium

 

TTT

I still could use an answer on the pre-87 heads going on a 93 block??

 

If its not an LT1 block then they will fit. Just the 87 differance is the intake bolt pattern on the 2 inner intake bolts are at a differant angle

 

So I guess that means that my Edelbrock TBI manifold will not work w/o some sort of "modifications?"

I hate slight modifications. They are never as slight as people make them out to be.

 

I dont know if he changed heads or crank or what ever, all i know is that just switching over from 1.5 to 1.6 ratio rockers you should not have to change push rods, if I am mistaken let me know.

 

Oh ya gunny hows the fleet? Im about to graduate ITB on the 27th of Jan, im home on recruiters assistance till the 4th cuz they shut SOI down for xmas (lucky me :lala: ) anyhoo, ill get my orders a week after I get back. Hopefully i wont go to a unit thats deploying. Not scared or anything at all, just scared of being bored out of my mind. Let me know, oh ya I hope ur not really a gunny and are a corporal like ur lil sig shows , damn NCOS

 

If he's going to use a roller tip rocker arm, yes he will have to double check it. If he's using a stock stamped rocker arm then no he wont. But one would "assume" that somebody spending this kind of money on a engine would get a set of roller rockers to free up a few extra ponies. Whens the last time you've ever seen a motor with aluminum heads and stock rocker arms
I'm sure there's someone out there that has done this, but it's almost like building a performance motor and not having it balanced.

 

I have the Trickflow 23 heads I like them I think? car isnt running well

 

Like the ZZ4 crate engine,The fastburn 385, the Lt4 and the LT1. The need for roller rockers becomes an issue as valve spring pressure increases. There are much more effective ways to make a few hp, especially if the rest of the motor isn't set up to make power when spinning 7000rpm.
Jm$.02,
Charlie

 

actually in this case is it a pretty slight modification, you just need to reangle the 2 inner bolt holes on both sides of the manifold, all you need is a drill and a decent eye.. no real trick 2 it.