# Some info on engine build please



## maktope (May 22, 2013)

I will be taking some time off work coming up and previously talked all over the map of buying a new engine. My questions is with out know how, but lots of patience time and books. And a good machine shop within driving distance. How much difficult would it be to tear down and rebuild an engine. Where would a good place be to look up what pistons cam yada yada yada i would need for my desired build. Honestly my motor isnt tired, just has a rear seal leak but p/o wasnt forthcoming with everything on the car so i just have a fear that the motor isnt what was stated. I would rather get ahead and make sure everything is solid, but if i am going to pull it to fix the seal i want more power out of it. If your questions is what power am i making right now, depends on the dyno but it is constantly between 411 on the low end and 439 on the high, with torque sitting between 499 and 507 at the rear wheel. I know i should be happy with it, but i would like to get that number up.


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## geeteeohguy (Feb 2, 2008)

If I were in your place, I'd do a compression test and a cylinder leakdown test. You're probably ok. If you are using no oil (other than the leaks) you are OK. I would pull the engine, install a one-piece or a Viton rear main seal, along with new gaskets and new freeze plugs. You can check the condition of the bearings when the pan is off. I would re-install the engine and drive the car. If you want to tear it down and rebuild it, with you doing the labor except the machine work, expect to be in it for at least 4k. If you have it built, expect to pay 6 to 8k. I have seen a lot of well intentioned but inexperienced guys pull an engine, tear it down, and lose interest or get side-tracked due to life and lack of funds. The car ends up a basket case, and sits for years. I have also seen a lot of expensive, but mis-matched combos put together due to lack of knowledge and research. The HP and Torque readings you currently have are excellent. I would take them and run with them in a heartbeat.


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## PontiacJim (Dec 29, 2012)

Just for fun, go to U-Tube and search for "Blueprinting Pontiac 455". This is a series of videos that begins with Part 1 and goes some where to Part 16. These videos show you what it takes and will at least give you some idea.

Next, I don't think it is too difficult to rebuild an engine, but most work will be done at the machine shop and you are basically assembling it. But in order to assemble your engine, you need to invest in the correct tools and equipment. This is an added expense and if you are only doing it once, then I am not sure the investment would be worth it. I suppose you could rent some tools, but that could be a hassle.

Geeteeohguy makes some good points. I don't know what size engine or what parts are in it. If you have good parts, ie forged pistons, rods, heads, etc., then you use this to work off of. You could simply have a machine shop "freshen" up the short block. If the bores are good, they can get a quick hone just to clean them up and ready them for new rings -fairly simple. Now if the bores are poor, then its time to bore the cylinders and oversize the pistons -which usually means a re-balance of your crank/rods/pistons, flywheel/harmonic balancer. The bearings can be checked and if good, you simply re-use them. Any issues that may appear, then the crank will most likely be ground undersize and new bearings will be needed.

I am going through all this myself on a 455CI and had hoped to just bore it out, go oversized pistons, and steel rods. Well, the block was real bad inside and thought I was going to sleeve a couple cylinders @ $200 a pop. Luckily, it took a .060" overbore and cleaned up. I bought pistons and rods and the crank had a spun bearing. Machinist thought it would clean up and he said the factory crank was extremely tough and I wanted to keep it if possible. Bad news was the rod bearing got so hot that it warped the crank/journal. Had to buy a new Eagle crank. Of course everything now has to be balanced. Now for me, I wanted certain pistons & rods, so everything I am doing is what I had planned except for the crank. It is adding up fast.

IF you were to find that you needed to bore your cylinders and go with oversized pistons, and/or you needed to have your crank turned, and/or you only have stock cast rods --then the best way to go is a rotating assembly/kit that includes new pistons & rings, rods, crank, bearings, & balanced (Butler sells these as do several other Pontiac builders, but Butler prices seem better). These are all the things you need anyway and will cost more to buy individually. BUT, this kit has smaller rod journals and uses longer Chevy rods for more "Free" cubic inches and less friction at the bearing. Big plus here. If you have forged rods in your engine, sell them to recover a few dollars. If you have forged pistons, but you need new ones anyway, sell them if they are good. (or keep it all for your next engine build).

You buy the kit, and let you machinist assemble the short block for you. Now if you feel daring, you can install your cam/lifters/timing chain& gears. If not, let the machinist install your cam/gears. -but it is not too hard IF you use care sliding it in. If your heads are good, you need not do anything, BUT if you want more HP, then the cam is where you get this. So you have to have matching valve springs to go with your cam choice. So you may need to have the heads worked -which is simple if just the springs. Again, don't know what you have for heads.

OK, now you have a completed short block and you don't have to worry about a leaking rear main seal or special tools, or busting a ring, or.....
Then you have your heads all ready to go. From this point, YOU can most likely bolt/torque the heads on the block, install lifters, pushrods, etc., install your intake/carb, distrib, exhaust, water pump housing, etc..

BUT FIRST, I would get a game plan going like I did and do some part pricing. Like geeteeohguy said, it could get pricey OR you could work with what you have. If your engine checks out OK, your HP & torque is not bad, but perhaps a different cam would get you to where you want and be somewhat cheaper.

So you have options -many of them. Just will take you to sit down and draw up a plan as to what you want from your engine, and then fill in the blanks with $$$$. I feel 425HP - 450HP is great for the street and you can enjoy it, especially if you go bigger cubic inches and build for torque and not for HP. Over 450HP and you may find the engine needs higher RPM's to work, is balky at lower RPM's, will only idle at 1,000-1,200 RPM's, has poor vacuum, and will require the drive train to match the engine needs - possibly more money. There was just a poster who had a 550HP engine and found it to be way too much for the street to be enjoyable and wanted to drop the power level down on it. Big HP can be fun, but not always an enjoyable ride if you plan on cruising regularly or taking it to car shows, let alone any long trips.

As always, I'm no expert and am still learning new things the hard way - as I always seem to do, and that equals more dollars spent than what I should have or had planned on.:banghead::yesnod:


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## maktope (May 22, 2013)

The engine is a 428 .030 bore with #64 heads. Was rebuilt roughly 9k miles ago. My problem is with previous owners statements on what was in the car that I know wasn't true i.e. Rear gears clutch wiring ect. I do not know for certain if cam pistons rods and so forth are as stated. Do not know where red line is for the motor. Dynoed to 5200 rpm still gaining hp. I know the engine was rebuilt but do not have information on who built it and original owner won't return calls. I've fixed almost all the issues that arose after purchase, then the seal leak which may have been from me switching to synthetic oil. My problem is I am just not sure of the quality of parts and what the engine can actually do. Tune guy swears I can pull 6k rpm that scares the crap out of me if it's not true and I am not willing to test it. As for leak down test, only oil loss is due to the leak, mechanic says from his point of view besides the rear seal the motors great. I have had problems with bent pushrods. Bent 4 of them exhaust on #3 cylinder twice.


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## ALKYGTO (Mar 29, 2010)

What Geetee and Poncho Jim said X 100. 

If I was going to determine the health of this motor I would do the compression and leak down tests and then pull the motor. pull the pan and you will be able to see if you have the good partd. Pull a rod cap and a main cap and check the condition of the bearings. Pull the heads and take them to a shop to have the springs checked and a valve job if it needs it. Sounds like you have a real strong engine :1:there. I would fix the oil leak and leave it alone.

If you want more power, keep this engine as is and build a big cube forced induction engine. That will minimize your downtime and you can build it with no compromises.

What do you want out of this car? You must have some goals, is it some big hero numbers or a performance goal? One of my favorite 69 ' s on here is owned by member JTWoods. His GTO is a handling beast and is a street legal car that looks stock but tears it up on a road course. 

What transmission and rear gears do you have? You are making good power, maybe a little more rear gear and an overdrive transmission would be a better investment for you.


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## maktope (May 22, 2013)

Have a Chevy 12 bolt 3.55. Have a 5 speed tko in the garage ready to install. Currently trans is a m20. My goals for the car I would like more street able power. She's good on the street currently. Obviously upgrading suspension is in the cards. I just have a nagging feeling about the engine. Compression test and leak down both good. Is the simple answer just replacing seal and head work or swapping to aluminum heads? KRE thinks so, and they have the product for me lol. They were very professional actually. For a year I've been posting going to do the motor now finally stars aligned. But hesitant because I swapped out intake carb and found some one who could tune the car and got big increase of dyno numbers but even though it says it's better she feels less. Huge power increase above 3k,


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## PontiacJim (Dec 29, 2012)

The 428CI is an excellent engine choice that combines bigger cubes and higher RPM's -best of both worlds.:thumbsup: You should have no problem spinning 6,000 RPM IF you have the forged pistons and rods. That said, ALKYGTO is correct in that the only way you will know for sure is to pull the engine and remove the pan to take a look inside. It sounds like your engine is solid. 

I have a TKO 5speed with the .64 5th OD gear that I will be using myself. Your 3.55's will probably be too stiff if you have the same trans. I think the other version is the .82 OD 5th gear. Use one of those gear/tire height/RPM/cruising speed to figure out your gearing. I am going with 3.89 (Ford 9" rear end to handle bigger HP) so that I can cruise comfortably at 70 MPH and not lug the engine. If you have the .64 5th gear, you won't be able to use 3.55's until you get way up in speed. If you go bigger on the engine, you have to estimate the RPM range your engine will maintain without getting lugged down. When you build a bigger HP engine, it requires more fuel. If you don't have enough velocity/air flow going through the engine, it loads up with raw fuel/carbon deposits and runs poorly. This is why a high HP engine runs better when you flog it all the time and buzz it. Try driving it real conservative at lower RPM's thinking you will squeeze out another 1 mile-per-gallon will only have your engine running poorly. Run the engine hard and you will notice how much better/smoother it runs and it is crisper when you do nail the gas pedal. Now this relates to carb engine, while fuel injection or throttle body meters the fuel precisely as needed and works better -but high dollars to add this to a Pontiac. 

I have been emailing Jeff at KRE myself as of late, with several questions about my selection of parts for my build. Fast responses, honest replies, and very helpful info in making up *my* choices. What I noticed is that he lets me do the asking and answers, but did not go into a "we recommend, or we do" rant or sales pitch. Now this helps to steer me in *my* build, as I have a solid idea of what I want, and then when it comes down to actual selection, I have no doubt that KRE's experience will provide a final choice that will work for me and my build and not necessarily something they want me to build as they see it. The KRE heads seem to have many good reviews. They go from basic out of the box to high-dollar flowed heads. As I have said in past posts, when you go bigger CFM's, everything changes within your engine and you may trade off lower HP & torque for big power improvements in mid-range and up HP & torque UNLESS you go bigger on the cubic inches which means it needs more air to begin with and it won't be quite as seemingly radical. So with the bigger heads & more flow, you may now need to revise what cam, intake, carb, headers, distrib. curve, as well as consideration to your gearing.

As you can see, if you start changing items on your engine, you have to look at it as a complete package that balances and compliments each piece you select. Not doing so is what makes some builds disappointing after putting a lot of money into some parts, but not matching them up.

Don't get over anxious and be in a rush because you don't want to take the time needed to do your engine build, or rebuild correctly. Have a plan of attack once you have your needed info on your engine.

Pull your engine to see what is inside. You want to pull it to fix the leak anyway, right? Then from there, you decide what you want to do. If you have forged pistons/rods, you have a good 6,000 RPM engine with the potential to now invest in upgrades like the KRE heads and bigger cam if that's what you want. Sounds like you have a good tuner and machinist nearby. Listen to them and talk with KRE on exactly what you have and want to do with your engine/car. The more info they have, the better they can match your parts to create the ride you want. 

Just remember, you can't have an engine that does it all, you have to basically select the RPM range you want your engine to work best. You don't have an LS-3 with all its made in China electronic fuel injection stuff or variable timing do-dads made in Mexico. This is where modern engines do indeed excel, but you have something that is a classic, and flat out raw brute horsepower that will shred tires at your command, and takes a real driver to harness and control. As and owner of the coveted GTO, you are also someone who has accepted the responsibility in preserving part of an era now gone so that others may know and come to have the same enthusiasm you have for the GTO as well as other Detroit muscle of that bygone time in AMERICAN history when cars made in AMERICA ruled the roads and captured the hearts of many a young motorhead. Either you get it or you don't.:cheers


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## Orion88 (Apr 24, 2012)

If you have a 428 making over 400 HP/500 TQ at the wheels, and it's streetable enough to be a daily driver, I think you'd be crazy to try to squeeze much more power out of it. However, aluminum heads will make a difference without hurting streetability, since they can handle higher compression ratios. With a well matched cam I don't see why you can't make a solid 450+ at the wheels and still be streetable. But I'm with these guys. If it ain't broke, don't fix it. I may be young but I believe in the old sayings. If you want peace of mind, with the oil pan off you will be able to inspect everything to give the motor a clean bill of health. If all that checks out and you want more power, aluminum heads, a well matched cam, an original intake, and a Quadrajet rebuilt by Cliff or with his book will not leave you disappointed. Beyond that just make sure your exhaust system flows well enough that you're not restricting your engine and if that still doesn't make you happy, cut a hole in the roof and supercharge that beast!


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## ALKYGTO (Mar 29, 2010)

Maktope, I run 4:11 gears in my 12 bolt and with the .82 overdrive tko I'm turning about 2500 rpm at 75+. I think you'll want a little more gear than a 3:55 and that will make the car feel a little quicker.


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## Orion88 (Apr 24, 2012)

On another one of your threads you said this engine dynoed at 415 ft lbs and 313 up at the wheels. Did you do any mods or adjustments since that post?


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## maktope (May 22, 2013)

Listed above changed intake carb exhaust and finally found someone who could tune


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