f-crazy

just a FYI you can use the stock brackets and serp setup with a LT1 motor...its just takes about 3 hours and a cut off wheel..

tpi_roc

z_power

Back from the past...

I'd like to use Gen1 intake with coolant crossover; have an idea of routing coolant lines. When you'll look at front of any EFI intake, there're at least 2 sensor holes, how about enlarging 'em to ~1/2" size and connecting with unplugged holes in frnts of heads? This way I could use stock thermostat housing; rear ports in heads could be connected to the heater or heater valve. CTS could be placed in T-joint together with one of new lines.
There're going to be clearance problems with serp. system brackets but I think they'd be soved with little amount of grinding...

What's your opinion?

edit: LT1 intake gaskets are positioned with pins and small hole in head surface, these holes must be welded or plugged of course

tpi_roc

Personally I think by the time you're done accomplishing that you've negated most the benifit of the LT1 head on a SBC combo which is the combination of the heads and LT1 intake, which becomes a direct bolt on instead of a conversion. The conversion is almost entirely in the heads. Not to mention to use a SBC1 intake on LT1 heads entails alot more modifications to get coolant to flow through the original coolant passage of the intake for the thermostat.

I wouldn't bother if it was me, unless using the LT1 intake.

nape

Would you mind sharing what cam you're using?

I'm thinking about doing the same thing and someone is selling a used LT1 cam around. You just have to cut the dowel pin off, right?

tpi_roc

In my opinion an LT1 cam is hardly worth your time taking the engine apart, its a stock cam for a stock cam, you can find plenty at decent prices to avoid one.

I'm running flat tappet so it wont help you but anything in a 230° range with a 112 lsa and as much lift as you can afford will match the heads well.

nape

Oh, it's not a stock cam. I'd rather not post the specs though.

It's somewhere in the area you recommended though.

Any idea on how much lift the heads can take in stock form? If I have to get screw-in studs I'll just run guide plates and save some money by using non-self aligning RRs.

Just picked up the cam the other day. I still need to find a deal on heads/intake/fuel rail and '93 TB [usable w/ 700R4].

How's your project coming BTW?

nape

TTT to renew interest. This is an awesome idea

tpi_roc

The heads went to the machinist again for new guides, they should be assembled and installed early this season. I'll be sure to post updates.

nape

I scored an LT1 intake with fuel rail for $20 locally, I thought I was only getting the bare intake. Too bad I already had a fuel rail coming from ebay for $50 I guess it'll just go back on ebay.

I started calling around to machine shops today to see if anyone has any LT1 heads laying around. One shop said they've only got iron ones and the other thought he might have a few laying around, I'm hoping he'll call back tomorrow.

All aluminum LT1 heads are fine, right? I haven't heard of any significant performance difference.

Once again, thanks for the pics tpi-roc. I'm going to bring them into the machine shop so they know exactly what needs to be done. How's your project coming?

__________________
3rd gen Firechicken. Midwest region American Iron #134

tpi_roc

My heads are done except for the hardware. I just blew up another rear so that dipped into the LT1 head funds for now but after buying some springs they can go on.

ajclark7

Do you have any pics of the cooling holes in the heads. I,m planning on doing the same to my heads and I would like to see how you did it.
THanks,
AJ

nape

Any more work done on it? I've had a few sets of LT1 head slip through my hands and I hurt a short block so I'm behind schedule.

Just wondering, I love the idea of $300-400 total for aluminum heads

__________________
3rd gen Firechicken. Midwest region American Iron #134

tpi_roc

Only thing they dont have is springs and guide plates. The rear still has priority. I'll be sure to post any updates on the heads.

TPl383

bump... any new news. a thread over on another forum got me wondering how your project is going. Someone over hear was asking if it could be done.

http://www.z28.com/showthread.php?s=...378#post147378

__________________
Powder & Thermal Coatings ~ Polishing & Chrome Plating. Custom CnC Billet Parts ,and more.....
-----------------------------------------
Droptop Z, 383 LT1 callies crank & rods, JE pistons, Single Turbo,Nitrous,Th400, Roll Cage ,Mini Tubbed,2 inch drop spindles,coil overs in all 4 corners,moser 9 inch w/willwood disks, Alloy Engineering Camber / Caster plates, complete 97 TA Int. and much more.........

New addition is a......
'87 Yellow Iroc, 350,A4, 9bolt with 3.45's 99k miles. Soon to have full aftermarket suspension & 383 LT1

tpi_roc

Hey chris,


No no news, they're done but the car still sits needing a rear. If anybody knows where I can get a smoke'n deal on some 3.73s or a solid rear for a low price let me know so I can put the heads on the engine.

TPl383

Ive got a drum brake, 3.42 posi rear end layin around.
Might let go of a 94Z rear end.

and I have a old ford 9inch with 3.00 gears.

tpi_roc

I'm pretty hard set on 3.73s, my car traps pefectly with them, untill they broke anyway

DuronClocker

Have any updates on this? I'm going to do it soon. I'm abandoning the LT1 intake swap and am going to do the LT1 head swap using a stock LT1 intake.

Did you have to re-drill the head bolt slots at all? There is something in that one link that mentions the head bolts being at a wrong angle, unless they were referring to the intake bolts because I know the intake bolts are different. It appears that in that link they ONLY swapped the heads and use the ZZ3 intake.

tpi_roc

Dont have any updates, someday I"ll put them on the engine....


There's no drilling necessary except for coolant and the distributor.

DuronClocker

Can you put up some details (or PM me, either way) on what kind of drilling you had to do for the coolant holes? I'll probably be using the stock brackets and serpentine setup since I just got my 1LE pulley in. The only accessories I have are alt, p/s, and w/p.

I don't have the heads here yet, I'll be sending the money in a few days. $250 shipped gives me LT1 heads with complete valvetrain, stock LT1 intake, and 24# injectors. Should be more than enough for a 305 with headers and an LT4 Hot cam.

Anyways, I'd like to get an idea of all the work that is needed to actually mount the intake and heads. I know how to deal with an LT1 intake by itself, and I have the remote tstat housing already. I'll still need to make up some fuel lines and coolant hoses, but that's no big deal. I can take this stuff in to school and weld the aluminum plugs in for free and then take it off to be milled (the mills at school are no good for heads and that type of stuff).

How hard is the coolant crossover, and what is the easiest way to do it? If you could send me some pics (dean@xibase.com) of the LT1 heads from different angles, that'd be awesome so I could see what I'm dealing with before it gets here. What do you have each of the fittings connected to on the remote t-stat? I don't know what connections should go to what fitting.

Also, if I did the math right, this will raise compression on a 305 from 9.3 to 9.8 using a stock .018" head gasket, right? That'll be perfectly fine with 89-octane with aluminum heads and stock (for the most part) timing.

Sorry for all of the questions, but its hard to figure this out without many pics or the actual heads in my hand. PM me or email me at dean@xibase.com with more info.

__________________
Nice weather car: 1998 Z28 LS1/T-56...11.92@118 with crappy driving last year. ATI Procharger D1SC'ed this year
Daily driver: 1995 Honda Civic DX with a 1.6VTEC/5spd swap. 43mpg and climbing
Old car: '88 Trans Am, 355ci with LT1 head/intake conversion slammed on C5's. SOLD

nape

Dean-

From what I've read, the only thing you have to do to the heads with an LT1 intake is to plug the end coolant passages and weld them, then tap the intake for coolant ports in the back. I believe you have to drill a hole for one of the locater pins as well, where you had to weld in the plugs.

-TJ

__________________
3rd gen Firechicken. Midwest region American Iron #134

DuronClocker

What's the smallest diameter coolant line I can run from the heads to the remote t-stat block?

Roostmeyer

I'd just use the 3/4" nipples or the AN equivilent that everyone's been using for converting the LT1 intakes. The 3/4" lines are tried and true. Also using AN fittings you should be able to find something with a 3/4 nipple and a 90 degree turn on them. On the heads you'd be able to turn them 360 when your threading them in, so it wouldn't be a problem like on the lt1 intake.

If I was going to do this though, I would place the nipples in the back of the heads, although it might take a little suggestive clearancing (enter the BFH and some wood to spread the impact a little). If your not running accessories you could have room in front of the heads.

__________________
88 T/A GTA, 408, cam motion hydraulic flat tappet cam, hooker catback, Coated hedmen LT's, cutout, Transgo Shift Kit, TCI 3800 stall, CAI, LT1 Intake, Pro Lightning 180's, SVO Red tops, 9-bolt: 3.70 gears, LS1 front brakes, KYB-GR2's, cut IROC springs, SFC's Hotchkis rear susension. Walbro 255. NX wet kit sitting in the parts pile.

tpi_roc

Personally I wouldn't run them in the back of the head. The LT1 engines have an inherant coolant system problem that comes with a sorta fix you can see just by opening the hood. There are already coolant holes at both ends of the head to help purge out air bubbles that cause cylinder hot spots and detonation. Since the engine tilts towards the tranny the highest point is the front of the heads, if you coolant exits there you have the best chance of blowing out those air bubbles. However the LT1 is reverse flow and this swap isn't so the problem might not even exist, I just wont risk it myself.

DuronClocker

:/ I was looking out the front and 90* nipples would be easier, but even then I don't know if I could squeeze the 3/4" hoses through there. 5/8" would probably work. I tried checking out the back but as mentioned, it'd require some serious clearancing.

EDIT: Yay finally 2 pages.

DuronClocker

Okay, on the drive side head, the coolant will exit out of the rear as there is plenty room on my car. On the passenger, there is NO room behind the head, so it will have to exit out front where there is a little room. There will be much more after some grinding.

Did have a question though. The coolant port on the rear of the passenger head has no plug in it, and looks like something was screwed into it. I'm assuming this was a coolant line. If these heads on an LT1 could use such a small coolant line, why can't they on my motor?

tpi_roc

^ read above ^

Igor

I have a 406 small block with flat top pistons and 2 valve relifs. Its new, has no heads.

I also have a complete lt1 parts car with a damaged block/crank (beyond salvage).

I could do this lt1 swap onto the 406 with lt1 intake, holley commander 950 ecu and harness, this combo could work. But what about Lt1 heads being able to handle steam holes for the 406. Also, I think the compression would be too high. 11:1 I could handle, any more I don't think I could.

ME Leigh

What is behind the coolant passages that are blocked off? Is it a big hole or just a little passage? I am wondering if it would be easier to pour molten aluminum in there instead. You might be able to stick some thing in the coolant passage so that the molten aluminum doesn't flow too far.

I'd like to put some LT1 heads on my 305 just for the weight savings, but i don't want to go through all the trouble of welding and crap.

Does anybody that has worked on LT1 heads have an opinion on this idea?

__________________
LT1 headed LG4 305 beast! Comp Solid lifter XS-262-10S, 1.6 Roller Rockers, 10.2:1, Holley 4160 600cfm, modded Weiand 7502 intake to fit LT1 heads____ Custom cylinder head cooling. Weiand 8208 Short Water Pump____TH-350 3 series 3.73 with 2 series posi and spacer____ Hedman Hedders 1 5/8 headers and Y-pipe 3in Exhaust, Dynomax 3" Bullet muffler ____Moroso Ultra 40 Wires ACCEL HEI Super Coil ____Competition Engineering 3120 Bolt-on SFC's____Homemade: Wonderbar, solid tie rod sleeves, Aluminum LCA and Panhard Rod with spherical rod ends, alternator and PS bracket, Strut tower brace, and Decoupling torque arm with telescoping link.
3000lbs

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tpi_roc

Not going to work.


There's nothing you can put in there to block molten metals flow, that you're going to be able to get back out, or that wont melt itself. You're also going to be pouring liquid hot aluminum into aluminum, which probably has a better chance of warping or damaging the deck surface. Then you still have to mill. You're not saving any time, trouble, or money.