impaled

i recently picked up a set of 374 LT1 heads and intake manifold and am going to port them at my school with my instructor. i have a few questions (as i am not in that class yet)...

i am going to run them through the jet clean, but to get them a little bit cleaner, what should i use? i have been using carb cleaner and a brush but it is going a little slow...

what size valves should i go with? and what manufacturer? and what is required for the bigger valves/valve job? would i need new inserts (setllite/ferrite, etc.) in the heads?

for the manifold i dont have a 58mm throttle body, so i dont need to port that in a big way, so should i just do the runners? or should i do the whole manifold?

is there a site or guide with info on porting LT1 manifolds and heads?

96capricemgr

iTrader: (1)

Ever heard the phrase "those who can't DO, teach"? There are exceptions but they are just that, exceptions.

Careful with degreasers on aluminum as most of them will do damage.
Brake parts cleaner may be helpful.

To go beyond 2.00/1.56 valves in the LT1 heads you need new inserts, lots of extra work and cost for no proven gain.

I would open up the inlet, just because you don't have a 58mm TB now doesn't mean you will never have one and opening it up wont hurt anything. Owning a good ported LT1 intake I can tell you it is not necessary to hog it out, though some folks do, to the point only the powdercoat holds it together.

impaled

i agree with the teaching thing, as he is willing to help me through the process, i just want to figure out a little bit more what i am getting into.

i was using brake clean as well and washing the parts after usage so that the carb cleaner wouldnt mess them up.

2.00 and 1.56 was what i was thinking due to LE and AI uses that on some of their packages.

i was also thinking of opening up the inlet anyways just to increase potential volume. i am not going to be too agressive on the intake. i just got it because it was only an extra $25 when i bought the heads. i researched that it flowed well and i wont take a ton of meat off of it.

impaled

what else do i need as far as parts go so i can have it all ready.

i was thinking of the crane kit 10308-1 for valve springs, locks and shims. but that only allows .600 of lift at 7k RPM, which is plenty, but i dont know if since i am dropping the cash if i should go bigger. i am thinking of the crane 831 cam with 1.6RR's (or should i go with 1.7RR's) and get a little more lift out of them?

note: i still dont know where to get as far as valves. brands, etc.

impaled

would these valves work... http://store.summitracing.com/partde...5&autoview=sku

they are manley 2.00 intake

but i cant find any 1.56 exhaust valves on summit. all they have is 1.60". or (1.50 which is stock)

what would you recommend for the seals and valve stems?

brokenbird

iTrader: (5)

i would use the 1.6 valves if you could they should flow better

T/A KID

iTrader: (12)

I think the correct way to port an LTX intake is to remove the top

impaled

they would but i dont know if i would have to machine into the insert , which would make machining a lot harder.

Formula350

iTrader: (3)

Use the factory LS1 valves. Cheap to get or find and lighter/bigger than LTx ones. Opening the exhaust up more would be more beneficial than the intake's.


LOL @ T/A KID. That would make things a hell of a lot easier for sure! Assuming his teacher has a tig and can weld like a pro :\

RamAir95TA

iTrader: (2)

Here you go again with wrong info. You CAN'T use LS1 valves on an LT1 head.

LS1 valves are 8mm (.313").
LS1 factory castings use a .502" guide.

LT1 valves are 11/32" (.341").
LT1 factory castings use a .557" guide

LS1 valves use a bead lock keeper vs. LT1 single square groove.

Sigh.

OP - Manley makes several varieties of valves, from budget to severe-duty.

T/A KID

iTrader: (12)

Welding on the stocker isn't too bad
Here is a pic of one I just cut up, weighed around 3.5lbs

96capricemgr

iTrader: (1)

It can be done.

T/A KID

iTrader: (12)

You can with a few modifications. Larry from speedinc has LS6 valves in his LT1 heads

T/A KID

iTrader: (12)

You beat me too it, lol

RamAir95TA

iTrader: (2)

I understand that it can be done, but for the application of the OP, he's more than likely better off picking up an off-the-shelf set. Formula350 suggested them, without any supporting information, that they can just drop right in. Mentioned nothing about "a few modifications."

impaled

i would rather just find a set of aftermarket valves that i can drop in. does anybody have a verdict in wether or not 1.6" would fit without putting an insert in?

Formula350

iTrader: (3)

lol It might not be too bad to weld onto, but if you start getting into the detail you are... That changes the game being played haha I'd like to see the finished product when you're done though


NOW who's backpedaling? We've gone from you saying "You CAN'T use LS1 valves on an LT1 head." to "I understand that it can be done". You don't post a ton of info to back up your claim of it not being possible, and then say "oh, well yea I understand you are able to" But yea, I'm still the bad guy here right? Just trying to help the kid out and give him an interesting project to do while at school with tools to utilize. Just wanted to give him some experience, since you're the one preaching about that so much and how important it is over just knowing the info. And since people upgrade their setups, finding the parts second hand would be fairly cost effective.

I believe what has to be done is you put in the correct sized valve guides and run the LS retainer and keepers. But hey, what do I know right? So I'll let Cap or T/A correct me, since you're unable to make up your mind on if you can or can't do this


You need bigger valve seats.

myltwon

iTrader: (1)

from my understanding stock bore LT1s benefit little if at all from larger valves due to "valve shrouding"

impaled

exactly what i was looking for. thanks Formula350.

now as far as the LS1 valves, what size are they?

but to run the LS1 retainer and keepers i would have to basically run two different valve guides and not be able to get a kit with springs locks and retainers? so i would have to get another valve spring package or only use half

impaled

good news... i found the right sized LT1 valves. i called summit and asked if they had any and they gave me manley's phone number and i taked to manley and they gave me the PN's

2.000" intake PN# 11500
1.560" exhaust PN# 11501

summit will dropship them for me.