Hey guys,

I'm finally on my way to putting a new motor in my firebird and need to figure out what cam and heads to go with.

It a vortec block with .020 tho pistons, just a pro comp stroker kit for the bottom end.

Roller lifters but will probably get a new set with the cam, i was looking at the xfi 280hr but i think it will get a bit pricey with the rest of the gear to suit.

I just want something with a nice lumpy idle and makes some decent power.

I have a set of heads that have been ported but have no idea what they are, but have access to some fuellie heads I could use, or just the heads off the current motor which are just whatever come with the gm 290hp crate motor.

Also on a bit of a tight budget so whatever can be reused from the current motor or what I've got would be good.

Also have a complete HSR with 30lb injectors granelli MAF etc and prominator for tuning, and the vortec block has whatever cam in it they were using for a speedboat motor.

 

also got some pics of the heads if anyone can tell anything from them?

 

3986336
Big chamber , low compression, smog heads

https://www.thirdgen.org/forums/engi...ing-heads.html

The heads you sold off the Vortec engine would prob been a better choice; at least they had some compression

 

yeah but then I couldn't use the HSR.

So I'd be better off finding some fuellies?
Or will I have to go for some aftermarket heads to use a xfi 276 or 280?

 

You are doing things backwards.
You select the head size required for the Hp ( decent power) output you are looking for , sort out the CR ( chamber size and pistons dish ) in conjunction with a cam that will work with that combo

A long duration cam ( the one with the lumpy idle you think you want ) requires more static CR than a cam with less duration

 

Without the Vortec heads that make it a "Vortec" engine ,it is just another 1 pce RMS block that is roller cam ready

So you need to identify what that cam is ; it may be of use in your build

So you need to identify what those are as well , the chambers are prob smaller to give you a better CR

# 93438648:
Not much different from your other heads .Low comp 76cc chambers

 

Almost, there's a slight difference with the timing chain section, it won't allow a double row set without grinding out some of the block material, but yeah, pretty much the same.

I don't think the heads can have much saved off, so I guess I might not bother with them.

The cam, I'll try to find a place that can measure it and tell me what it is, or maybe find a grind number or something on it.

But i guess I'll chuck the other heads from my motor on it and just save and get a set of afr 1040's

With those and a XFI280 cam I'll probably end up saving money on a tune if I can find a tune on here seeing as it seesm to be a pretty popular combo yeah?

 

I think people get confused by parts selections in terms of what is offered in the aftermarket when it comes to heads/cams with strokers.
They build a stroker which naturally is a lower end torquer,then see promoted huge heads relative to rpm range and cams that build hp taking away some of the low end.This comment is related to normal street use.
The above paragraph is the simplest explanation of a much more complex solution which is more involved.It doesn't make much sense to spend on a stroker unless you capture what all SBC's offer in head/cam combo's.It is the primary area when the money gets spent.Nor does it make much sense to get to that topic and when "cheap out" on a stroker.If that is the game plan,might as well saved the stroker money and applied it to a head/cam combo on a 355.
The 383's respond to a well planned out,executed,cam timed,exhaust ported,exhaust system.It is a key trait of all 383's and important.

A clean intake charge will come back to you ten times over after a good exhaust evacuation at any level,at any compression,at any end use.

Hitting the target quench of .040 to .035 with head/head gasket/ block deck numbers and doing your best to avoid using steel thin shim head gaskets is also very important.

With the variances it today's pump gas to hold a standard of a SCR of 9.5 with cast heads and a DCR of 8.5 or a SCR of 10.5 and a DCR of 8.5 with aluminum heads is also a factor.I've seen time and again guys go to two extremes where they are saddled with 76cc smog heads and then "try" to use milled 58cc heads @ 0 deck.Some with disastrous results.This is your build,your money and not someone else's adventure.

 

Yeah, i know I'm in over my head, my mate at work is going to build it for me as he used the be a mechanic and has all the tools and know-how, but as for what I want, i just want something with a nice lumpy idle, torquey motor maybe 400hp ish.

In australia all the sbc parts seem to be ridiculously pricey, so finding something 2nd hand or cheap seems alsmost impossible. And despite the sbc's being one of the most common motors int he world, doesnt seem to have many parts available.

The car is my daily and it'll probably see a few quarter mile runs a year max, rest will just be street and cruising.

I figure the hsr should be enough without porting to meet my needs, and the exhaust has extractors is dual 2&1/2" system with no cats and 3 pass resinator on each, I'm gonna get them changed over to a single pass later down the line. Transmission is stage 3 shift kitted and built to handle over 500hp, toque converter, not too sure but i think its a 2200.

Diff is open 2.73(7?) 9 bolt which will be replaced with a lsd when i find one i can get in australia.

If I can find a head/cam combo with a tune as well I'd be willing to take the hit on shipping from the states, but it doesn't look promising.
Last time i tried to buy something from the states I ended up losing money to a scamming bastard.

 

Not the reply from you I was hoping for.None of us where born knowing this stuff and it is available to you to learn,apply to your car car too.

 

Here is something to sink your teeth into written better than I could,but I totally agree with:


http://www.crankshaftcoalition.com/w..._compatibility


http://www.crankshaftcoalition.com/wiki/Quench

 

Hi to a fellow southern hemisphere inhabitant. You've gone from smog heads and a cam that you know nothing about to looking at AFRs, arguably some of the best available. If this is the tack you are taking then it would be wise to sort the compression and then get a really good cam designed for your application. Anything less would be wasting the potential of those heads. Perhaps even a custom cam would be worth it in the long run. All IMHO of course.

Cheers

 

See you are already on the wrong path; the " lumpy" idle is a byproduct of the combo you end up with , not something you build for
In any case ,cams with "lumpy" idles are generally not compatible with EFI ECM's unless you have have a very good tuner which you are lacking in Brizzy

Exchange rate to USA will never be better and even with the shipping cost , most parts will be nearly half the price what local retailers are asking.
Always cams for sale on here under $250

 

280xfi is a great cam for a 383. I use it on my 385 with Brodix 200ik heads..Sure it would make even better power with the AFR heads your thinking about.

 

go more cid

 

Have you looked at his disjointed thought process?
He started off with "on a bit of a tight budget so whatever can be reused from the current motor or what I've got would be good"
and now he is talking about $$$ AFR heads

Stuie needs to get his act together and work out how much Hp he can actually afford
As they say ;Hp costs , how much you got to spend ?

As Gary already noted , a successful engine build requires thought and planning ; not just throwing together a selection of random parts ,some of which may have worked on someone else's build.

 

Why did you build a SBC anyways if it was so hard getting parts? You should've pulled a LS motor out of a wrecked Holden instead and swapped it in. LS parts are plentiful over there. That money could then be applied towards performance as opposed to brutal shipping costs...

 

Decided to go another way, found a cheap 400 motor so i'm gonna drop that in instead, pull the old motor, rebuild it and sell it for heads money.

Thanks for the info guys, didn't really get the ideas I was after, but you get that.

 

You get back what you put in.
All you stated was a cam you hoped to use in your 383, some random heads you have lying around and a limited budget that would hopefully give your desired outcome.
Not much for guys to work with

 

Well I asked for cam and head combos.
I said what I had and if I could use them it'd be great, but I was after a cam and head combo that would possibly have a tune out there I could use and is a known quantity.

I'm sorry if I wasn't clear on that, so that's my fault.

 

A certain part of me regrets not see where you live and you clearly stated that.Sorry I missed that.Then,giving my background in these forums,another part of me says you guys know going in how shipping costs can effect build costs.
I'll stand behind the info I provided to you that a informed consumer(you)will be you best bet after you have looked at the links and understood them.Trying to use someone else's combo,there is like that car magazine articles a equal chance of building someone's gains and yes very high likelihood losses.

As you gain knowledge that reduces that chance is huge.

 

Evilstuie - a few links off the top of my head for sbc parts in Australia - if prices not listed rule of thumb I use - take the Summit item price and multiply by 1.7 (or 2.5 for heavy castings like heads, blocks). Or just or from Summit, Jegs etc usully cheaper, esp with the current exchange rate.


http://www.rocketindustries.com.au/
http://www.eagleautoparts.com.au/
http://stores.ebay.com.au/Engine-Mas...id=p4340.l2563
http://stores.ebay.com.au/CHRIS-MILL...id=p4340.l2563
http://stores.ebay.com.au/AT-RACING-...id=p4340.l2563