[gtofreek]

I'm starting the engine build for my GTO, finally. It's funny, but I've been an engine machinist/builder for almost 22 years now and this will be the first performance engine I have built for myself. Previously, since being a machinist, I have only built 2 engines for myself. The 2.8L V-6 in my S-10 pickup[stock], and a re-ring, and bearing job on a 389[stock] I did on a 66 GTO I had a while back.

I'm planning a N/A 400 for this project. It will be .065" over with a bore of 4.185", and a stock stroke of 3.750". This will make it almost 413" CID. I'm starting with a 1967 400 block that is .030" over now. I have cryo treated it already, now it's ready for me to grind off all the casting flash, and de-burr it. Then it will be shot peened to get it really clean, especially in the water jackets, and the look of new cast iron. I have a set of 1967 670 heads I will use also. My target for performance is 550+ torque, and 650 HP, and to run up to 8000 RPM, on pump gas.

Short block:
Will be filled to the bottom of core plug holes with HardBlock after threaded grade 8, 1/2" x 13 rod is threaded into block deck down to bottom of water jacket. Done to help stiffen the deck some.
Connecting rods will be Callies Compstar 6.700" BB Chevy H-beam with L-19 rod bolts. I will have pistons from CP in a couple weeks. They are 2618 material, and feature a short, stout, 2.5" long .990" piston pin with steel gas nitrided 1.5mm, 1.5mm, 3mm rings. They will be flat top. A stock 1967 400 cryo-treated crankshaft will be used after grinding the rod journals down to 2.199". Lifter bore brace will be installed. Block will be align honed with ARP studs, zero decked, and bored and honed with a torque plate, and ARP head studs. I'm going to run a solid roller cam that I will have Jeff Koerner, and Harold Brookshire help me design for exact needs. I have some Crower HIPPO roller lifters for it.

Heads: I'm starting some major reconstructive surgery on the heads this weekend. They will be nothing like a stock 670 head when i get done. They will only be recognizable by the casting number. I'm redesigning the combustion chamber, and trying to convert it to a fast burn design. I figure I will need these heads to flow 275 CFM or better to meet my goals. I flowed a bone stock port[#2 cyl.] tonight with stock valves, with no backcuts on them. I was very pleasantly surprised on how well it flowed. I have flown a lot of D-port heads, but never a 670. Most D-port big valve heads flow around 204/165 I&E. This head flowed 218/190! It is as cast. The thing that surprised me the most is the fact that the flow never turned over like most other D-port heads do. In fact, this head flowed more air up to .300" lift than a ported set of #62's that I have that flow 255 @ .450" lift. I'm going to try something unconventional with the intake valve. Below are the flow numbers from this head.
I have a Victor intake manifold I will be porting to match these heads when I get them done.

I will work side by side with Jeff Koerner to build the perfect Holley carb for it.

I'm trying to build this engine for $2000 to $2500. Since I can do all the labor myself, in house, I should be able to, or at least be close.

..........Intake_______Exhaust__E to I ratio
.100"= 82 __________54________66%
.150"= 118 _________76________64%
.200"= 149 _________98________66%
.250"= 173 _________115_______66%
.300"= 193 _________130_______67%
.350"= 202 _________143_______71%
.400"= 208 _________157_______75%
.450"= 211 _________165_______78%
.500"= 212 _________171_______80%
.550"= 213 _________177_______83%
.600"= 214 _________181_______85%
.650"= 215 _________186_______87%
.700"= 215 _________188_______87%
.750"= 216 _________190_______88%
.800"= 218


Pictures to come.

[GOAT WHORE]

8000 rpm Nice!
So what do you anticipate the finished combustion chamber to cc at? And that will make the static compression ratio what?
Looking forward to following this thread Paul.

[Cliff R]

670 heads have a very good intake port, and get even better when you open up the chambers some and unshroud the valves.

Power goals are obtainable with the combination of parts. Not sure how "streetable" the engine will be, considering the valve springs required to safely spin it to 8000rpms on a regular basis. With the heavy internals of the Pontiac design, and smaller cross-section in the runners we seldom look at twisting them that hard and focus on mid-range power instead.

I have had thoughts of taking one of the new blocks and putting a 3.75" stroke crank in it with KRE high ports. Tried to talk a few customers into that deal but they went the "505" route instead. Can't blame them, as the cost to build the engine is just as great and you get more power at lower rpms with the 505cid deal.

It'll still be cool to build a high winding Pontiac 400. You must have a LOT of parts laying around and left over from other projects to get it done for under $2500. Solid roller cam, good springs, HIPPO lifters, valves, retainers, pushrods, decent full roller rockers and a timing set will eat up a good chunk of the budget. Looking forward to some dyno sheets on the end product......Cliff

[steve25]

Paul the 670 heads have a lower port angle ( not valve inclination angle) then the other D ports and this is the main factor in there greater flow numbers, if you look close at the top side of the head below the rocker studs and compare that to the latter heads you can see how much that change is in the casting.
Just last year I had the time to mess with a 670 head and just with a quick bowl clean up and a elliptical valve job that picked up the air speed on the exh valve side of the chamber the air flow hit 235 cfm.
This valve job makes better use of the heads port bias and guides the air better into the center of the cylinder which helps with the stock closed chamber,, but as you will see with your rework to a more open chamber to hit Intake flow numbers above some 245 cfm@28" that chamber must be reworked as you are planning to do!

[HWYSTR455]

Subscribing...

Closed chamber heads have a distinct 'smell' when the engine runs, in stock form of course. It's been a while since I've had the pleasure though!


.

[68azbird]

Yeah buddy

[gtofreek]

I got some parts already[good leftovers], plus I get a better deal on parts than most people do. Adding up the main parts I still need comes to around $1800, but you know there's always stuff that comes up that you don't think about. I have a roller cam credit. I have most of a set of slightly used HIPPO lifters[need to buy 2]. I have lots of Ti retainers that are in good shape to choose from. I need valves and maybe springs[Might have a good set stashed at work, just need to see what my final installed height will be.

Being a 4 speed car, I have no need for a smooth idle[wide lobe sep will bring the power band higher, and mellow the idle some]. No need for a lot of vacuum, since I'm not running power brakes[leg strength here baby!]. It obviously won't be a trailer queen or daily driver. But I'm not putting a roll cage in it either to make it drag race legal. I may put a roll bar in it. Have to be mellow on the launches, though as I don't want to break my Muncie. I will need to buy some beef up parts for it. The 9" Ford I am going to build should be up to the task though.

Originally Posted by Cliff R

670 heads have a very good intake port, and get even better when you open up the chambers some and unshroud the valves.

Power goals are obtainable with the combination of parts. Not sure how "streetable" the engine will be, considering the valve springs required to safely spin it to 8000rpms on a regular basis. With the heavy internals of the Pontiac design, and smaller cross-section in the runners we seldom look at twisting them that hard and focus on mid-range power instead.

I have had thoughts of taking one of the new blocks and putting a 3.75" stroke crank in it with KRE high ports. Tried to talk a few customers into that deal but they went the "505" route instead. Can't blame them, as the cost to build the engine is just as great and you get more power at lower rpms with the 505cid deal.

It'll still be cool to build a high winding Pontiac 400. You must have a LOT of parts laying around and left over from other projects to get it done for under $2500. Solid roller cam, good springs, HIPPO lifters, valves, retainers, pushrods, decent full roller rockers and a timing set will eat up a good chunk of the budget. Looking forward to some dyno sheets on the end product......Cliff

[gtofreek]

Originally Posted by GOAT WHORE

8000 rpm Nice!
So what do you anticipate the finished combustion chamber to cc at? And that will make the static compression ratio what?
Looking forward to following this thread Paul.

I need to see how this chamber comes out. I really don't know. Shooting for 11:1.

[hurryinhoosier62]

Paul, sound like a great combo for drag racing.

[gtofreek]

Yeah, that too! I definitely want to run it down the 1/4, even if it's only once!

[hurryinhoosier62]

Be sure to post LOTS of pictures, especially of the combustion chamber mods.

[gtofreek]

OK. Just got done working some on the cracked 670 head. I angle cut the deck .100"[tilted the head .100" from the intake surface to the exhaust surface] to remove some of the "hook" in the combustion chamber. Also, I wanted to get the spark plug closer to the piston, in an attempt to get the air/fuel charge burned faster, to give it less chance of detonation. Doing this got the spark plug .085" closer to the piston. Deck thickness still looks good. This also made the chamber considerably smaller so I have room to open it up without making it too big. This also will slightly alter the port angle as it enters the cylinder, effectively moving the valve opening more towards the center of the cylinder, slightly. This did slightly improve air flow. Intake picked up at every lift point, while the exhaust picked up a fair amount at low lifts, and lost a slight amount at higher lifts. Angle cutting should also gain me more pushrod clearance with 1.65 rockers. I may not need to grind the pushrod holes out. We'll see. Below are the new flow numbers, followed by the gain or loss. More pics as well.

_______Intake____Exhaust____gain/loss
.100"___85_______57_________+3/+3
.150"___121______80_________+3/+4
.200"___153______99_________+4/+1
.250"___178______116________+5/+1
.300"___199______131________+6/+1
.350"___201______143________-1/0
.400"___206______152________-2/-5
.450"___209______163________-2/-2
.500"___212______168________0/-3
.550"___214______173________+1/-4
.600"___215______181________+1/0
.650"___217______182________+2/-4
.700"___218______186________+3/-2
.750"___219______189________+3/-1
.800"___220_________________+2
______________________gain = +31/-11

[gtofreek]

[rexs73gto]

I think the size of your engine is a bit in question as I think with the bore cut at 065 over & the crank cut to you going to be a wee bit bigger. My math isn't very good when it come to this but wonthe total be closer to something like 425 when all said & done. ???? Myself I wouldn't use the 670 heads. It sounds like your just hoing to build a very strong engine, so why not go for a good set of Alum. heads, like , Elelbrock, RE, or one of the unfifnshed heads that you you can put all that work into & then you'll be well over your HP limit.????

[A.W.Dille]

Rex there is nothing wrong with 670 heads. I'm waiting to see what the final result is with these mods as I'm planning to have the chambers worked and bowl work done on mine whenever I get to point I can start on the new engine for my GTO.
Besides Paul knows what he is doing and doing this on a cracked head is better than trying this on the heads he planning to use so he can determine gains and loses in port flow and velocity along with burn rate.

[gtofreek]

Originally Posted by rexs73gto

I think the size of your engine is a bit in question as I think with the bore cut at 065 over & the crank cut to you going to be a wee bit bigger. My math isn't very good when it come to this but wonthe total be closer to something like 425 when all said & done. ???? Myself I wouldn't use the 670 heads. It sounds like your just hoing to build a very strong engine, so why not go for a good set of Alum. heads, like , Elelbrock, RE, or one of the unfifnshed heads that you you can put all that work into & then you'll be well over your HP limit.????

4.185" x 4.185" = 17.514225 x .7854 = 13.75567231 x 3.750" = 51.58377116 x 8 = 412.6701692 CID. Rounded off to 413 CID.

How could I possibly stay within my budget if I buy aluminum heads? They would cost me my entire budget. I can't/won't do that. I'm not made out of money, and if I have to save up for aluminum heads also, I'll never drive my car. Besides, anyone can make power with aftermarket heads. I want to make aluminum head HP and torque, with factory iron heads. It's more impressive to me to do that. Plus, it's a challenge. I like challenges. I want people to be shocked when they see my car run, then they see a 67 GTO engine in it when I pop the hood. That shock factor won't be there if they see aluminum heads. I need to do this on the cheap, spending my money where I really need it.

[Tom Vaught]

Originally Posted by gtofreek

OK. Just got done working some on the cracked 670 head. I angle cut the deck .100"[tilted the head .100" from the intake surface to the exhaust surface] to remove some of the "hook" in the combustion chamber. Also, I wanted to get the spark plug closer to the piston, in an attempt to get the air/fuel charge burned faster, to give it less chance of detonation. Doing this got the spark plug .085" closer to the piston. Deck thickness still looks good. This also made the chamber considerably smaller so I have room to open it up without making it too big. This also will slightly alter the port angle as it enters the cylinder, effectively moving the valve opening more towards the center of the cylinder, slightly. This did slightly improve air flow. Intake picked up at every lift point, while the exhaust picked up a fair amount at low lifts, and lost a slight amount at higher lifts. Angle cutting should also gain me more pushrod clearance with 1.65 rockers. I may not need to grind the pushrod holes out. We'll see. Below are the new flow numbers, followed by the gain or loss. More pics as well.

_______Intake____Exhaust____gain/loss
.100"___85_______57_________+3/+3
.150"___121______80_________+3/+4
.200"___153______99_________+4/+1
.250"___178______116________+5/+1
.300"___199______131________+6/+1
.350"___201______143________-1/0
.400"___206______152________-2/-5
.450"___209______163________-2/-2
.500"___212______168________0/-3
.550"___214______173________+1/-4
.600"___215______181________+1/0
.650"___217______182________+2/-4
.700"___218______186________+3/-2
.750"___219______189________+3/-1
.800"___220_________________+2
______________________gain = +31/-11

Great work on the heads

Tom V.

[gtofreek]

Originally Posted by A.W.Dille

Rex there is nothing wrong with 670 heads. I'm waiting to see what the final result is with these mods as I'm planning to have the chambers worked and bowl work done on mine whenever I get to point I can start on the new engine for my GTO.
Besides Paul knows what he is doing and doing this on a cracked head is better than trying this on the heads he planning to use so he can determine gains and loses in port flow and velocity along with burn rate.

Exactly!

[gtofreek]

_______Intake____Exhaust____gain/loss
.100"___85_______57_________+3/+3
.150"___121______80_________+3/+4
.200"___153______99_________+4/+1
.250"___178______116________+5/+1
.300"___199______131________+6/+1
.350"___201______143________-1/0
.400"___206______152________-2/-5
.450"___209______163________-2/-2
.500"___212______168________0/-3
.550"___214______173________+1/-4
.600"___215______181________+1/0
.650"___217______182________+2/-4
.700"___218______186________+3/-2
.750"___219______189________+3/-1
.800"___220_________________+2
______________________gain = +31/-11

I forgot to average the gain/loss. Basically, the angle cutting helped the intake out with an average gain of 2.06 CFM per lift point. While the exhaust lost an average of .07 CFM per lift point.

[gtofreek]

Originally Posted by Tom Vaught

Great work on the heads

Tom V.

Thanks Tom!