Heads for my LT1 truck - pixxxx
12-31-2007, 06:33 PM
#1
Heads for my LT1 truck - pixxxx I am putting together a motor for my LT1 truck, it will be a little more suited to the weight and towing it will be subjected to.
It is basically stock. Standard bore, stock crank, rods, pistons, timing set, pushrods, rockers, and lifters.
Custom 206/212 .480/.487 110LSA Comp cam. Valve springs good to .550 lift so I can upgrade to 1.6 rockers and other valve train parts down the road.
The cylinder heads are the 561 castings. I did a little work on the chambers to bring the compression down and improve flow, and figured while I was in there I would do some bowl blending and knock the valve guide bosses down since they are huge in stock form. I didn't do any reshaping of the ports for a couple reasons. First being I didn't want to add any volume to the runners because this will be a truck motor that needs to make a little low end. Secondly, this is the first time I have done anything like this. I have no porting experience. Did this in my basement in about 6 hours from start to finish. It's pretty time consuming!
Before smoothing
After smoothing
I still have to get the valve job done and get them surfaced. Don't worry about the marks on the seats! You can't feel them with your finger nail. I was going to polish up the chambers and exhaust ports, but I ran out of sanding rolls and my buddy was ready for me to bring the heads to him so his dad could do the valve job and surfacing, so I am stopping here. They're just truck heads
It is basically stock. Standard bore, stock crank, rods, pistons, timing set, pushrods, rockers, and lifters.
Custom 206/212 .480/.487 110LSA Comp cam. Valve springs good to .550 lift so I can upgrade to 1.6 rockers and other valve train parts down the road.
The cylinder heads are the 561 castings. I did a little work on the chambers to bring the compression down and improve flow, and figured while I was in there I would do some bowl blending and knock the valve guide bosses down since they are huge in stock form. I didn't do any reshaping of the ports for a couple reasons. First being I didn't want to add any volume to the runners because this will be a truck motor that needs to make a little low end. Secondly, this is the first time I have done anything like this. I have no porting experience. Did this in my basement in about 6 hours from start to finish. It's pretty time consuming!
Before smoothing
After smoothing
I still have to get the valve job done and get them surfaced. Don't worry about the marks on the seats! You can't feel them with your finger nail. I was going to polish up the chambers and exhaust ports, but I ran out of sanding rolls and my buddy was ready for me to bring the heads to him so his dad could do the valve job and surfacing, so I am stopping here. They're just truck heads
01-01-2008, 10:34 AM
#4
Stock heads are like 170cc, you can add port volume without hurting torque so don't use that as the reasoning for not working further up the port.
Valve job is all important, hope he knows what these heads like because a Serdi with a three angle cutter is NOT the beall endall most little local shops believe it is.
Valve job is all important, hope he knows what these heads like because a Serdi with a three angle cutter is NOT the beall endall most little local shops believe it is.
01-01-2008, 11:26 PM
#7
It's going to be in a heavy lifted truck with 38" tires that tows quite often. High compression isn't ideal for that. It's not going to be real low. I don't have a burette to CC the heads but it should still be low 10s or mid-high 9s I would think. I'm not too worried about it on this motor.
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01-02-2008, 04:36 PM
#8
The b-body LT1 was 10.0 with iron heads and the tow package was good for 5000lbs rating, the wagons and Fleetwoods were 4600lbs.+ empty and ran on 87 octane. Do not worry about lowering compression.
If you took say 2ccs out of the chamber going with the thinner Felpro head gaskets would keep it about stock 10.4 compression, I would consider doing that.
If you took say 2ccs out of the chamber going with the thinner Felpro head gaskets would keep it about stock 10.4 compression, I would consider doing that.
01-02-2008, 10:04 PM
#9
I am going to be towing in the range of 3-7,000lbs. I already do but it is a dog with the stock F body cam and gears. I haven't geared the truck yet, it still has 3.73 gears LOL. Basically every time I have the money to gear it something comes up and the money is spent on one of my other vehicles or bike parts. I am going with 4.88s, they should be a nice gear for it. It will turn approximately 2200rpm in over drive at 70mph.
I am running the B body specific Victor Reinz head gaskets (OE). They are .029 compressed.
I am running the B body specific Victor Reinz head gaskets (OE). They are .029 compressed.
01-02-2008, 10:13 PM
#10
Yeah with that much tire the 4.88s are a good choice, similar to a car with 3.73s.
Far as the towing, I should have mentioned the b-body tow package was 2.93s, the Fleetwood was technically a d-body, just a stretched b-body really but it got 3.42s with the tow package.
Point being with aluminum heads, your compression is going to work just fine. The b-body motors had to contend with a really crappy gear out back and 87 octane. Long as the tune is good I see no problem with your setup.
Some of the b-bodys even wagons got 2.56s but those were just a 2000lbs tow rating.
Far as the towing, I should have mentioned the b-body tow package was 2.93s, the Fleetwood was technically a d-body, just a stretched b-body really but it got 3.42s with the tow package.
Point being with aluminum heads, your compression is going to work just fine. The b-body motors had to contend with a really crappy gear out back and 87 octane. Long as the tune is good I see no problem with your setup.
Some of the b-bodys even wagons got 2.56s but those were just a 2000lbs tow rating.
01-02-2008, 10:53 PM
#11
Yeah I got ya. It's really kind of impressive the truck rides and tows and good as it does. It is lifted quite a bit and handles and rides just about like stock. It's a smooth ride and the chassis tows very well. Just need to get good gearing. With the current motor in it (stock LT1 from my TA, approximately 105k miles) and the 38" tires and 3.73 gears it still manages to get 13mpg. People think it would be good on gas because the RPMs are low, but not at all. It's always under a load. I can't wait to see what kind of MPGs I can get with this new motor and a good tune, and some gears. I'm hoping to see an improvement but having better towing power will make me happy enough. Stick that trailer behind it and it turns into a dog and gets 9.5-10mpg. Take the trailer off and it pulls itself very well.
01-11-2008, 05:40 AM
#17
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SWEET truck! I had 2 lifted Suburbans, I miss my black one (90, TBI). I wanted to do so much stuff to them, but couldn't. I also wanted to go a little faster, but couldn't. So I traded my 86 with custom chameleon flames and 6" lift for mt 91 Firebird. Now I miss the 91 Bird lol
Anyways, the motor in that truck looks really slick.
Anyways, the motor in that truck looks really slick.
01-11-2008, 10:21 AM
#18
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Truck looks good man! how much lift is that? I had 9 on my old truck before I got the camaro, and I know how you feel being undergeared I had 3.42's in mine w/ a 37" tall tire.
Pic:
Pic:
01-11-2008, 11:15 AM
#19
Good looking truck man! Mine should be right around 10-11. It had a 3" body lift and 6" suspension lift but I added leafs and messed with the torsion bars to bring it up a little more. It rides and handles like stock! It might actually go around turns better than stock.
