The Stovebolt Site Forums The Shop Area The HiPo Shop 1995 LT-1 heads on a 85 350 block

I've got a set of 1995 Z-28 LT-1 Aluminun heads that I want to put on a 1985 350 that I had on the engine stand for about three years.
It is a 4-bolt main with steel crank . Bored 30 over with speed-pro 11-to 1 pistons . I don't need 11-to 1 on the street, the steel heads that I WAS going to use would have put the c.r. at 9 , using a 73 cc chamber.
Can the LT-1 heads do the same ? I understand that there are some drilling to be done for cooling but what else can I look to do to use these heads.
Thanks , George Hood

George,

I don't think you can use those heads on that 85 block. The 95 LT engine has reverse coolant flow, and there isn't any coolant passages from the manifold to the head. Your better bet would be the Vortec heads or the GMPP fast burn heads. You need the right intake for the Vortecs but they work really well, I have a set on my 70 Nova and I love them. Hope this helps.

Sean

Geeze I wish some one would answer this post. I"m thinking of the same thing.

Have you poked around on z28.com? I wanna say it can be done,, but it has been too long since I worked @the machine shop. Brian

According to the GM Performance catalog, those heads are for Gen 2 smallblock only. It doesn't really give a reason as to why, but I'm certain the it has to do with the cooling configuration of the engine.

Seems like the old boy @the machine shop drilled the heads & intake both in order to use them. May even used an external crossover in the rear. Coolant goes thru the heads different than the older engines. Ol' JD is 67 & been a machinist all his life, has had his own shop since 1975(still in the same place). If I get a chance I will ask him about it. Seems like he said "it ain't sposed to be done", but he did it quite often on circle track engines if the guys couldn't pony up the $$$ for Eagle or World heads. Brian

George

I work in a machine shop and if you have the heads I am thinking of, there is no surface cast under the head to close off a water port if it were to be drilled in the correct location. You may be able to heil-arc some aluminum and form the passage walls you need, but this would come at a high price and be iffy at best. The drilling of the heads that 64 Fleetside is refering to may be for the intake bolt pattern on the iron vortec heads from 96-02. That is something circle track guys do quite often. I did my vortec heads this way and I would not recommend doing it. The end holes in all four corners break into the water jacket and are difficult to keep from seeping. Hope this helps

Sean

Sean,Brian,Bill, Thank You all for the input.
I now witch way to go now. Sell the LT-1 heads and buy new Vortec .
Any one need LT-1 heads.
George Hood

George,

One question, are the speed pro pistons domes? If they are they won't work with the chamber in the vortec heads and the compression would be sky high (aprox 64 cc chambers). If you have flat tops and a cam with 230 @.050 or more duration, and you keep the total timing around 30 deg total you can usually run 91-93 octane gas. I like to look for cranking compression in the under 190 psi range to run on pump gas. I hate to make this complicated but it all has to work together.

Sean

No Sean, I am not referring to the bolt holes but the coolant passages. Now that you mention the casting being thin there, I can remember JD saying something about some heads being able to mod & some being too thin. As I said it was kinda stopgap for circle track engines-may not be desirable on the street-"redneck engineering","rigging" maybe, esp. being the cost of aftermarket heads are really not that bad(but too much for roundy racers). I am pretty sure the hole drilled was kinda small, I think a coolant passage was tapped into the rear of the intake(external, intake drilled & tapped & a coolant hose from one side to the other). It has been a while & the old memory ain't what it was-but I know I saw them on engines that worked-but I got no idea how well on the street. Seems I can remember a leaker also that we put iron heads back on. Brian

Brian,

Thats a new one for me, it must have to do with the rules at local tracks and what racers will try to get away with. The big thing around here was to drill the vortecs for the old style manifold the put perimiter bolt valve covers on them and try to pass them off as lesser heads. Again real redneck rigging.

Sean

George,
Are these stock aluminum LT1 heads ? If not I'm interested .

Sean, The pistons can go from 11-1 down to 9 -1 if used with 76 cc heads (I think,it may be 73cc)I'd have to look back in my old files.
What I started out to do about 9-10 years ago was to build a 1970 LT-1 350/370hp replica motor. Over the years I had gathered up almost all the internal parts and was told that the pistons would match the factory combo with the right heads. They were and still hard to find so the project went on the back burner for many years.
The oringal GM manifold and carb were sold and the exhust manifolds stole. Still have the factory soild lifter cam w/lifters in the GM tube and lifter boxes.
The bottom end is finished so I am now just look to put togrther a mid-range hp engine.
This engine project was put on hold about 10 years,but have'nt we all that love cars an trucks done something like that for some reason.
George Hood

Sean, I think here you can run any head as long as it is OEM, not aftermarket. Claimer motors, as they are called. Brian

George, sounds like a nice package. Your best bet for heads might be the Dart Iron Eagles if you want to go cast iron or the Edelbrock aluminum heads work well if you want to spend the money. Either way the heads can be ordered with a small or large chamber to keep the compression in check (the Vortecs are about 64cc, they might give you trouble). I understand about being on hold too, my Nova has been in the garage for 4 years due to a health issue and then a rust problem I am trying to sort out and then I am trying to build my 69 C10 to tow the Nova to the dragstrip. I live about 40 miles from the track and if one little thing goes wrong, you have no way home if you drive the car, I learned this the hard way. Good luck with the engine sound like you have a great start, I like solid lifter cams!!!

Sean

Brian, I think for a while at the small local tracks around here they baned the vortecs, but I'm not sure, we do more drag engines (and alot of grocery getter junk that pays the bill I guess) than roundy-round stuff where I work.

Sean

Sean, all the drag tracks are at least 100 miles away or so, although they are 'sposed to open one in Little Rock. Lots of roundy round tracks tho-I can hear one on Fri nite-just about 10 miles away from me I guess. My buddy ran the Iron Eagles on a sb400 in a 69 C10-very good on the street & track both right outta the box. He got down to consistent low 12's last year, full steel truck w/A/C & power steering. He added nitrous & lost time due to spinning-no more room for bigger slicks w/o tub work. This is the only pic I can find, the white 69 in the background behind old black truck. He frame off restored it then decided to race. Not bad $$ for complete ready to go heads. Good to hear others also have their projects on hold also-may keep me from giving up on mine-I got 2 kids that take all my time & $$$ so my project is stalled. Brian

WOW we came along way from the question of will the 1995 LT-1 heads bolt to a non LT1 block .If you want a set of Iron eagles I have a new set less valves never been built.Bronze guides screw in studs and NO the LT1 head will not work on your block it has a reverse flow cooling system.

Brian, don't give up !
You have to much invested and more to invest in to your young'in . Time will sort it all out.
IF you build a hot-rod car/truck,someone else is looking to buy it from ya ,or rip you off .
If you guide a hot-rod son/dauther they will be there.
My son is 30 now and sure he uses more shop space than he should .has more questions than I can anwaer . I love it
Sean, Let's stay it touch.
61 suburban , E-mail about the heads
George Hood

Hey George

Just glad I could help, I this stuff every day.

Sean