racer442olds

iTrader: (2)

NEW to the LS World. Looking to build a SBE LQ4 NA Bracket Car. Looking for advice on heads, intake, cam, fuel system, Exhaust and Iginition. Willing to spend the money necessary to do it right the first time , just hoping to save some cash by using the stock bottom end.

Car is as follows:
1977 Cutlass, TH400 4k Stall Ultimate Converter 4.10 Gear 8.5 Rear, Car ran 12.20s with a Stock build 455 but shes getting tired and i would like to go faster.

Already have a complete steel headed LQ4 with harness waiting on me to buy the parts for it.

Any advice would be appreciated. completely at a loss with where to start on this top end.

Thanks

KCS

iTrader: (20)

It's going to come down to whether you want to run a cathedral port head (LS1/LS6) or a rectangle port head (LS3/L92). LQ4's have dished pistons so you may want something with a smaller chamber to keep the compression ratio up.

racer442olds

iTrader: (2)

Which heads are better for a sbe? are the l92 too big?

KCS

iTrader: (20)

There isn't a real answer, everyone is going to have an opinion.

For a street car with a long runner OEM style intake manifold, I would go with the cathedral heads. They're smaller and tend to make more average power throughout a lower RPM range.

For a race car with a carb style or hi-ram intake manifold, I would go with the LS3 heads. They're bigger and tend to perform better at a higher RPM range.

The other thing to consider is that the LS3 heads start out with ~68cc chambers, which will help compression a little compared to the iron heads on there now. However, a 243 head has a 64cc chamber and the 862 heads start at 61cc. Either of which will raise compression even higher and still safe for pump gas.

racer442olds

iTrader: (2)

It's a race car, not worried about pump gas as I think I want to put it on methanol. if I go ls3 head what's the best intake and cam for that combo?

KCS

iTrader: (20)

A Holley Hi-Ram is probably your best bet, besides a fully custom sheet metal intake, and assuming you have the hood clearance for it. CID is also supposed to be releasing a badass single plane intake for the LS3 heads as well.

As far as the cam goes, you may want to talk to a sponsor. They'll want to know more about the car (gearing, trans, compression ratio, RPM range, etc) to help custom tailor a cam for your application. My guess would be something in the 23x/24x range.

A.R. Shale Targa

iTrader: (2)

OP may want to find another donor engine
Dont the early iron headed LQ4 engines have a unique and goofy crankshaft flange. Specific distance or something weird like that
Good excuse to put a stroker rotating assembly 408 together and with some stock LS3 heads make 11second power in that bigger car

mjs1012

iTrader: (36)

You can still use the 99-00 lq4, just need a custom converter if you're running a 4l60e. But since he's using a 400, he'll be fine with whatever he does. I'm building a 2000 lq4 but picked up a 01+ crank so it makes it easier for my build.

pantera_efi

iTrader: (1)

My LS-1/7 Eight Stack intake (IR) with eight 65 mm butterflies will allow the engine enough air for maximum power AND the measured runner pressure is 118 KPA (1.5lbs boost) at song. (N/A - no Turbo/SC)
Thus this IS the most powerful intake available for use on a LS engine with either a LS-1/2 or LS-7 head port.

This intake WILL require hood modification.
The average power increase is 75HP on a 346 CID, 100 HP with larger engine sizes.
I will send dyno/setup sheets to prove my above statement and a magazine article about the first 346 CID/600 HP LS engine. (11:1 with 236/242 cam)

The next item is the EMS choice, use/fit one that is easy to calibrate at the track.

My ITB kit includes the Redline ECU-882C, the same one that Robbie Shaw used the win his division championship in NHRA.

I would also suggest the use of my IGN-1A coil, the one required by NHRA for Pro-Stock.

Would you like more information ?

Lance

Fishmasterdan

I did a similar build as you. I would spring for decent set of heads . I also would go the ls3 route. I would look into 60cc or less chamber's for better compression.

racer442olds

iTrader: (2)

purchased a set of stock LS3 heads, now how much to mill, which cam and which intake.

A.R. Shale Targa

iTrader: (2)

Few problems to camming this thing. Dished pistons and large chambers means you can't get the compression up to mid tens without milling a bunch. But the the giant 2.165" intake valve loses precious clearance
I would mill twenty. Run .040" Cometic head gaskets and an EPS 218/232 cam with a factory LS3 intake manifold

ragtopz28

iTrader: (57)

Just as a comparison...not saying the best combo, but it did OK. SBE LQ4(426whp 383wtq through a stalled auto (acceptable I guess in 98* heat w/heat index at 106*)). It has a "nitrous" cam 231/247 and milled to 65cc L92 heads. LS3 intake and NW92TB.

racer442olds

iTrader: (2)

Heads turned out to be 243s not the LS3 Heads. If anyone has a lead on some PM me, i have already looked at what is available in the classified section

ragtopz28

iTrader: (57)

They are on here all the time in the $500-600 range. What didn't you like about the ones in the classifieds currently?

A.R. Shale Targa

iTrader: (2)

Send 243s to AI for the 232cc treatment. They'll make a bunch of power

ragtopz28

iTrader: (57)

That's what I plan on doing on my 2nd "back-up" LQ4 I just picked up. It is a fresh stock rebuild (just like my other one) so it should be a good test to see which heads make more power (with a correct speced cathedral port cam).
Rectangular vs. Cathedral for top end performance track only car.

ragtopz28

iTrader: (57)

Keeping this up for more input on the best H/C/I for a stock LQ4, for an all out bracket car.

Fishmasterdan

Sorry but there is a million ways to go about what you want. For me I went with 243s milled CNC titanium valves. Fast 102 rt. Thin head gasket for max compression and shooting for .030 quench, and a spec cam.

Fishmasterdan

O ya a little nitrous plate kit will take you into low 10 or high 9 if your wanting to go a little faster.