tpi_roc

I'm in the middle of the process of Installing some LT1 heads on my project 385 stroker, here's some pics of step 1.

tpi_roc

tpi_roc

tpi_roc

tpi_roc

For the unaware.....

LT1 heads have the same bolt pattern (block to heads) as GEN1 blocks have always had, they however were designed to go on a reverse cooled engine, and part of the cooling system entailed two new coolant passages per head. These passages are what are now blocked off in the pictures with some 3/8" inch (.375) 6061 T6 Aluminum bar. If these are left unblocked, coolant will dump right into your lifter valley.

The plugs were cut to 1" x 1.5" rectangles out of some aluminum bar about 4" wide cut into strips with a hydraulic iron worker (faster than a hacksaw), then cut in half down to size. Then I took a piece of tape and put it over the coolant passages, and then cut it out, using the cut out piece of tape as a template taped over the plug, then diegrinded the shape out. I then cleaned the 'rough cast' out of the coolant port, and made sure they were a close match and then tapped them into place about an 8th of an inch below the deck surface.

#4 was the first one I did, as you can see its a little rough, i made the plug so that it would start in the hole, and then figured i could pound it in, i was wrong, it got about flush, but went no further, so i beveled thee port and plug hoping it would loosen up wherever it was snagging, didn't work, eventually drilled it out and started over.


These are in the back of the 'roc and heading off to be welded, each plug has a beveled edge to help the weld get enough penetration into the plug to hold, after that obviously the head will need to be decked.

A side note, the intake valve seat is DAMN close to the deck surface of the head, it wont be able to be decked much more than fly ****.

tpi_roc

As for an intake, what I'm going to be doing is mounting a gasket matched stock LT1 intake with a distributor hole and spacer and walla, I'm good to go.


Coolant will exit the front of the heads where there are already threaded coolant holes (coolant return to radiator on stock LT1's - Z28ra(i)cer) that I'm going to enlarge and use the same coolant nipples that John uses on his converted LT1 intakes, the fuel and coolant will otherwise be routed the same way that John does.

Fevre

Interesting but it begs the question 'Why?' Do thsoe heads over something you could not get from a diff head that required no modification and had about the same cost?

Always looking to learn, thanks in advance.

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tpi_roc

Cost.... what cost?

Heads: $200
Intake: $40
Distrib spacer: $25
Welding: $50
Decking: $50
Porting: Free

KNOWING that endless LT1's are running 12's, and 11's, with stock heads, intakes, and a cc305/cc306 cam...priceless



But seriously, A few bucks, a little porting, and I'll have one of the trickest setups running some smoke'n times (on my stroker) for virtually a drop in the bucket compared to a HSR/super/mini(ram) and some aftermarket heads (roughly $1,700 total on the conservative side).


Thats why

5SIZ

you sneaky little bastard!


looks great man! I can't wait to see how it turns out.

f-crazy

roc i got a question for you..

u mentioned that fly sh!t couldnt be cut away from the deck because the valve seat is right on the deck..

i think i have that problem on my LT4 heads. the chambers were 54.4 cc but the guy i bought them off of cleaned them up to 54cc and installed 2.02 /1.60 valves

if i stand the head up and look down the deck i see a very small pice of each intake valve sticking out past the deck...

i know its not a good thing but is it actually bad?


the pics u posted didnt work for me..id like to see your progress

Ed Maher

Definitely cheap and good heads when you can do the work yourself.

If you can't, you would have to be completely stupid to pay a machine shop to do the work when you could buy better heads for the same price though, as already intimated above.

Ed Maher

f-crazy, the problem he is talking about refers to the intake valve seat being so close that if the deck was cut more, the seat would get cut.

If just some valve is sticking up past the deck, that's OK, thats called 'valve margin'. Now if you open the valve and you can see a flat spot in the seat where the deck is cut into it flat, that would be bad and probably not seal.

f-crazy

ohh ok i see what your sayin...

well its just the lip of the valve stiicking out..they heads came assembled so i i havent seen the seat itself, but from what i can see the seat hasnt been touched.

thanks ed!

tpi_roc

I apologize guys, the pictures will be up tomorrow, a router died.

Fevre

So you are running the LT1 intake also? makes more sense now.

I like trick stuff even if doesn't always make sense.

tpi_roc

Yup and the only thing that needs to be done is the distrib spacer


1 hole beats fiddy of 'em

tpi_roc

here is a picture of how the plugs started their life




:lala:

f-crazy

were are u gonna mount the thermo?

tpi_roc

probably the fender next to where the hard fuel lines turn rubber, or there about, i have no evap can or anything to worry about it wont be hard to find a spot

Roostmeyer

When i read about converting lt1 heads I thought damn this looks good on paper! I didn't want to have to be a guinea pig, but damn its good to see someone up to the task. Just a few Q's Are the coolant ports the highest part of the heads? (air bubbles, bleading the coolant?) What cc are the heads stock? Also are the exhaust ports same as standard SB chevy? I might need to talk to a friend with an engine fire lt1 tommorrow...

Its good to see someone take on a project and think outside the box.

tpi_roc

Yea the stock coolant ports are at the highest corner of the water jacket, doesn't look like there's going to be much oppertunity for air pockets in the head. As far as CC I'm not exactly sure but i doubt its much more than an L98, they're not increadibly large, they just flow well stock, port nicely and there's always the big brother "LT4" if this turns out well enough. The exhaust ports are "D-port" like aluminum L98 heads.

86 IROC

The combustion chambers are 58cc stock - FYI.

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1972 SS 454 Chevelle - 4 speed, Father/Son Project. 49K orig. miles, full resto.
1991 Z28 5.7L - 90' C4 L98, built 700R4, ACT 2900 stall, ported base & plenum, BBK 52mm TB, SLP Tri-Y headers & ORY, cut out, UD crank pulley, MSD 6A, Comp 1.6 rockers, 24# injectors, DIY tuning. Low 13's... I hope.

gmgod

Damn that is a good cheap way to a good heads/intake combo. Do you think there will be any cooling issues though?

Roostmeyer

The only other issue that i can think of is how your accessories will hook up. where are you going to mount the alternater, ac, and anything else? it doesn't seem like you'd have a lot of room to run even just a barebone setup with the coolant hoses coming off the front of the heads. Would it be possible to beat the **** out of the firewall, and switch the heads (right head on the left side of the block) and run the coolant out of the backside of the engine?

tpi_roc

Dont need to switch the heads, there are exits both front and rear, you could just drill both, and then plug the ends you dont use. I dont expect any cooling issues at all, so far everything looks like it will go great. My accessories are "bare bone" the only thing thats going to be in the way is the alternator which i'll remount if need be, no worries.



and FYI back most LT1 heads CC less than 58cc

tpi_roc

This is from mortec to the guy who threw in the 58cc thing...


10128374...92-up...350..........Gen.II LT1, 53cc, angle plug,
aluminum, reverse flow cooling,
175/68cc ports

jkris53406

Wow,
I am planning the same thing in the near future. I got the set from my buddy for helping him part out his smashed 94. I was hoping I would be the first one on the board to do so but it doesn't look that way. What size coolant hoses are you running from the heads? Also, what are you using for fuel lines? Thanks for any help.

tpi_roc

Fuel lines, coolant lines, and remote thermostat housing are all from millican, as far as being the first, I'm not even the first, this project although not very popular (yet?) has been done before us by thirdgen members.


I didn't necessarily seek out the hardest way to build an engine, I'm just poor and this is the cheapest way to my goals

SATURN5

Amen !

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gmgod

This is the first time I've heard if such a thing. I've been wishing and waiting for holley to make a HSR for vortec heads but this looks like a good alternative. Please let us know how it turns out.

tpi_roc

Given the stock 175(ish)CC size intake runners of LT1, and the fact that I'm using a stroker, I will probably eventually end up using the LT4 Heads and intake, theres your vortec alternative


Although that one isn't cheap

jkris53406

Any news yet?

tpi_roc

Blown up transmission shortly after the install of a converted LT1 intake on my engine kinda prolonged this project a little bit. As soon as i get a new transmission in the car I'll be back on the head project, I'll post pictures of the welds before decking, and after decking sorry for the delay.

Chris Etemadi

How about a little write up?
I was thinking of saving for AFR 195's but I too see your point in many Lt1's with stock heads and CC305/305 or XE 230/236 cams pulling low 12's high 11's.
So it wouldnt be too hard to mount the cooling hoses on the back of