Leave Stock Heads or port and polish w/ Cometic Head Gasket??????

[87GNT]

Hello-

So I have a completely stock unmolested 2nd owner 1987 buick grand national with 90k miles on the drive-train. I took the drive-train out and freshened up the 200 4r BRF transmission thus far. Now my plan is to start focusing on "spring cleaning" the engine with new (valve stems, comp valve springs, melling oil pump kit, rear main seals, timing chain, 180 thermostat and a few other items. I've been told to NOT break the seals on the heads unless I have too...prior to taking out the drive train I got 150lbs PSI on every cylinder with the compression tester.

So, should I take out the stock iron heads and have them inspected at an engine lab and while they are out have them ported and polished and go with ARP bolts or should I leave them as is?

My goal is to run in the 11's quarter mile which I know I can accomplish with stock irons. I plan on upgrading the stock turbo to TE-44 down the road but for now I am going with the stock turbo/injectors and get the car running as it should before I start throwing money into after-market stuff..

Your advice and experience is greatly appreciated.

 

[psycho6cyl]

Going for 11s I wouldn't touch it. Maybe new chip with injectors. Also make sure basics are covered. If fuel pump is stock just replace it and add a hot wire kit if you don't have one. Also get yourself a scanmaster. If you have said above covered then put it make maybe new valve seals and springs and put it back together

 

[greeneyegi]

if i planned on driving alot,i would do it once and get it over with.but if i was driving it 1k a year or less,leave it .150 psi a piece sounds good to me.

 

[Nick Micale]

Since you asked for opinions you will receive many different ones, so I will give you mine as the 11 sec. goal was prevalent in the early turbo Buick years.

Your goal is easily and reliably reached with simple bolt-on's as we have had a few GN get into the 10's with un-opened engines.

It is also smart to take one step at a time to reach your goal so you can verify the performance is improving and there is no sacrifice on reliability.

Your no. 1 item should be to replace the timing set, but I would NOT mess with the factory oil pump. If you do not have an oil pressure gauge, get one in the car.

When you upgrade to a TE-44 you may have to upgrade your converter, definitely if you use a precision exhaust housing instead of the Garrett housing for decent street response.

With your PTC intercooler and I "assume" a 3" downpipe, you will easily run in the 11's when you install new injectors and chip and decent traction.

 

[87GNT]

Since you asked for opinions you will receive many different ones, so I will give you mine as the 11 sec. goal was prevalent in the early turbo Buick years.

Your goal is easily and reliably reached with simple bolt-on's as we have had a few GN get into the 10's with un-opened engines.

It is also smart to take one step at a time to reach your goal so you can verify the performance is improving and there is no sacrifice on reliability.

Your no. 1 item should be to replace the timing set, but I would NOT mess with the factory oil pump. If you do not have an oil pressure gauge, get one in the car.

When you upgrade to a TE-44 you may have to upgrade your converter, definitely if you use a precision exhaust housing instead of the Garrett housing for decent street response.

With your PTC intercooler and I "assume" a 3" downpipe, you will easily run in the 11's when you install new injectors and chip and decent traction.

So i just recently installed a hotwire kit and I also purchased 42lbs 009 injectors, 42lbs TT 5.7 chip and PTC 10' LU 2800 stall converter that I plan to install once I have the stock setup unning as it should. Seems like the consensus is to leave the heads A LONE unless I have a mechanical reason for removing them.

 

[OhioC5]

Mine runs 11.70's and the only thing I've done to the heads is change the valve springs. My car has a lot left in it. I'm leaving the line at "0" lbs of boost too. I'd leave them alone.

 

[84BuickGNYorkPA]

I would at the minimum have the valve seats cleaned up and lapped in, at 90,000 miles it won't hurt anything. My local NAPA machine shop has a "performance" cutter they used on my old heads years ago, that would increase the flow.... not breaking the factory head gasket for the sake of not breaking it, makes no sense to me, (but I have heard this myself over the years). As all mechanics know, there is free horsepower to be found in the heads with a few simple tools; machinist bluing, new gaskets used as a template, a scriber, and a grinder to port the intake manifold, heads and exhaust manifold to each other.

Chuck

 

[DCG]

I bought a low mileage long block off a board member. Thought I was just going to drop it in but they let it sit open for years with dexcool in it. This solidified in the water jackets so I had to pull the heads for hours of cleaning. Ported bowl blended gasket matchedand sent to the machine shop. All the exhaust valves had stem ware but not the guides. To me that seems like it deffinetly hurt spool up, boost, and performance. Installed with new springs, arp bolts and felpro gaskets. Still waiting to fire it though. I would pull them.

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[Chuck Leeper]

@90K while you are changing the timing set, pull the cam out, and take a look. New springs are adding load to a well used cam. [Not to mention jacking the boost to run 11's]

 

[Mr.Spool]

leave the heads alone for 11 seconds.porting the heads will just lower the boost number to hit your goal.a 44/49 on a stock motor with a garret ex housing is a lot of fun on the street and will hit your et goal.

 

[87GNT]

Mine runs 11.70's and the only thing I've done to the heads is change the valve springs. My car has a lot left in it. I'm leaving the line at "0" lbs of boost too. I'd leave them alone.

11.70 NICE! Ok so I will leave the stock irons on and perhaps port the intake manifold to increase flow by using a new gasket as a template then. Thank you all for the solid advise I really appreciate it.

leave the heads alone for 11 seconds.porting the heads will just lower the boost number to hit your goal.a 44/49 on a stock motor with a garret ex housing is a lot of fun on the street and will hit your et goal.

@90K while you are changing the timing set, pull the cam out, and take a look. New springs are adding load to a well used cam. [Not to mention jacking the boost to run 11's]

Ok so inspecting the cam for flat areas and leaving the heads as is a good start?

 

[Chuck Leeper]

11.70 NICE! Ok so I will leave the stock irons on and perhaps port the intake manifold to increase flow by using a new gasket as a template then. Thank you all for the solid advise I really appreciate it.




Ok so inspecting the cam for flat areas and leaving the heads as is a good start?

Pretty much what I'd start with. The condition of the bottoms of the lifters is a good indicator.
Keep the lifters IN ORDER. [Or, take them out, 1 at a time.]

 

[Nick Micale]

Hello-

So I have a completely stock unmolested 2nd owner 1987 buick grand national with 90k miles on the drive-train. ............

I just want to add comments which I think would be relevant in this case.

A few years ago I purchased a 1987 GN from a local 2nd owner with 140+K miles which would pass for a 40K mile car. With some add-on upgrades and only valve springs and a timing set this car ran low 11's for a long while.

Another local owner with a 240K mile GN thrashed that on the street and would run low 12's at the track and did this for a couple years until it finally gave up.

I could go on with other high mileage GN's, but my though is to go have fun with the car with minimal mods while you are learning, and do the mods as you go!

 

[87GNT]

I just want to add comments which I think would be relevant in this case.

A few years ago I purchased a 1987 GN from a local 2nd owner with 140+K miles which would pass for a 40K mile car. With some add-on upgrades and only valve springs and a timing set this car ran low 11's for a long while.

Another local owner with a 240K mile GN thrashed that on the street and would run low 12's at the track and did this for a couple years until it finally gave up.

I could go on with other high mileage GN's, but my though is to go have fun with the car with minimal mods while you are learning, and do the mods as you go!

Thanks everyone for chiming in I really appreciate it. I will refresh the obvious things that would be a good idea to replace on a 90k mile car...(timing chain, valve stem and seals, rear main, water pump etc...) and will leave the heads alone for the time being.

 

[OhioC5]

Good move.