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Rebuilding my 300, some doubts

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julianc
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Rebuilding my 300, some doubts

Post #1 by julianc » Wed Apr 03, 2013 10:14 am

Hi to all, I m currently rebuilding my 300. It is bored standard measure, it will go on a Bronco 81 and I m looking for power between 1000-5000rpm. I need to buy pistons, rods, camshaft, pushrods, lifters, rockers and valves. I m rebuilding it myself since i m studying mechanical engineering and i want to learn and enjoy the rebuild.
Have already bought bearings.
Probably I will go for Keith Black Hypereutectic pistons to have a 9.0-9.2:1 compression ratio.
I don t know which connecting rods to go for, any recommendation ??
I m now looking and searching for the camshaft, i was told to go for solid lifters so i need a solid lifter camshaft so i m in with Schneider Cams.
I don t know what length should i go for in pushrods.
The rockers i have some doubts since i don t think that if i modify the ratio to 1.7 or 1.75 i will gain performance because i m running very low rpms, what do you think ?? Also i want to go to all proven stuff since i want durability and trust in my motor because i will make a lot of kms. I m thinking on roller rockers.
What valves should i go for ?? Stock OEM or maybe another brand.
My biggest concern when buying all this stuff is the relation between them. an example with camshaft rockers pushrods and valves. When i go for the camshaft, should i buy certain rocker or they are the same for all the camshafts. Same with the valves, should i choose different lenght of valves if i choose certain rocker, or they are independent. What about pushrods, if i have my cyl head and block decked a little bit to flatten the surfaces, how do i choose the length of the pushrods ?? Or there is a certain tool to know the exact lenght of the pushrod ??
I m spending a lot of time in research here because IMO it is one of the most important part when rebuilding the motor.
Thank you very much to all.
Juli

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StrangeRanger
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Re: Rebuilding my 300, some doubts

Post #2 by StrangeRanger » Wed Apr 03, 2013 8:02 pm

5000 RPM on the street? Really? You will be happier below 4500, so will your engine.

Hyper pistons are the ticket.

A set of properly prepped,polished and peened OEM connecting rods is all you will ever need or want.

Whoever told you to go to a solid cam was in error. A good hydraulic is quieter, lower maintenance and will make every bit as much power in the RPM range you are discussing. Something like Crower's 19212 or
Crane's 503905 should do nicely.

If you go to an aftermarket cam, it was designed for the stock 1.61:1 ratio rockers. Upgrading to roller rockers is a good idea but do not change the ratio. You absolutely, positively must use an all metal set of timing gears. The late model phenolics will not last with high lift cams.

You really won't know about pushrods till you get it all together. Machining the block and head for cleanup alters the cam to rocker arm distance and can require a different pushrod.

At your RPM range, stock valves are just fine. A good 3-angle valve job and some pocket porting of the valve bowls along with polishing and CCing the chambers will do you a world of good.
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

BIG 6 farmer
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Re: Rebuilding my 300, some doubts

Post #3 by BIG 6 farmer » Thu Apr 04, 2013 12:27 am

X2 on what Strange Ranger saying. For your Bronco, you should be looking at closer to a stock rebuild. But with some upgrades to enhance the low speed torque. You didnt say if you where using stock manifolds? Pick parts that work together from idle-4000 rpm. Look @ sticky on top of Forum page on, " FAQ". Some good info. ya need there, Follow that & you will be happy. :D
83 F 150 SB 4x4 300 six NP 4speed - - 1950 IHC L162 (1&1/2 ton?) - 87 & 88 T-Bird Turbo Coupes - 2000 Triumph Tiger , 76 Honda GL 1000 , & other toys and parts (& junk) -

julianc
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Re: Rebuilding my 300, some doubts

Post #4 by julianc » Thu Apr 04, 2013 2:02 pm

StrangeRanger wrote:5000 RPM on the street? Really? You will be happier below 4500, so will your engine.

Hyper pistons are the ticket.

A set of properly prepped,polished and peened OEM connecting rods is all you will ever need or want.

Whoever told you to go to a solid cam was in error. A good hydraulic is quieter, lower maintenance and will make every bit as much power in the RPM range you are discussing. Something like Crower's 19212 or
Crane's 503905 should do nicely.

If you go to an aftermarket cam, it was designed for the stock 1.61:1 ratio rockers. Upgrading to roller rockers is a good idea but do not change the ratio. You absolutely, positively must use an all metal set of timing gears. The late model phenolics will not last with high lift cams.

You really won't know about pushrods till you get it all together. Machining the block and head for cleanup alters the cam to rocker arm distance and can require a different pushrod.

At your RPM range, stock valves are just fine. A good 3-angle valve job and some pocket porting of the valve bowls along with polishing and CCing the chambers will do you a world of good.

BIG 6 farmer wrote:X2 on what Strange Ranger saying. For your Bronco, you should be looking at closer to a stock rebuild. But with some upgrades to enhance the low speed torque. You didnt say if you where using stock manifolds? Pick parts that work together from idle-4000 rpm. Look @ sticky on top of Forum page on, " FAQ". Some good info. ya need there, Follow that & you will be happy. :D


You have been very helpful. I m having my head port and polished with the 3 angle valve job done. I ll go for offy dp manifolds with a 390cfm 4bbl carb and custom headers made down here in Argentina. I am now less doubtful but my last doubts arise when choosing brands. I ve done a lot of research in cams but there are so many brands that i can choose one, do you know the best one in quality, or the most chosen because of its quality ?? What about the roller rockers which brand is mostly used ?? You are right of hydraulic lifters, most of the brands make them it was so strange to me to look for solid ones; what abould roller hydraulics or flat tappet hydraulic ones ?? I m asking for brands because I want my motor to be really reliable no matter the price :). Thank you all Juli

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StrangeRanger
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Re: Rebuilding my 300, some doubts

Post #5 by StrangeRanger » Thu Apr 04, 2013 2:58 pm

Crane, Crower, Isky and CompCams are all reputable, reliable brands and all make cams suitable for your application. Go to their websites and read what they say about their various grinds. Since you are going with a carb instead of EFI you have many more options in cam selection. You do not need or want a roller cam for your application. They are way more expensive and add very little if any performance in the RPM range you are planning on.

As for the roller rockers, two very big questions first:
1) Does your head have round holes or oblong slots where the pushrods go through it? It makes a huge difference in what you have to do for roller rockers
2) does your head have bolt-down rockers or pressed-in studs? It makes a difference in what you need to do to convert to roller rockers. Whether you convert to rollers or not, if it has pressed in studs, you really want to tap it for screwed in studs

Also, be aware that roller rockers will probably not fit under a stock valve cover. You will need to either cut and braze 2 stock valve covers to build a taller one or to buy a taller aftermarket cover like a Clifford or an Edelbrock (which are no longer being made and extremely hard to find)
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

julianc
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Re: Rebuilding my 300, some doubts

Post #6 by julianc » Fri Apr 05, 2013 12:31 pm

StrangeRanger wrote:Crane, Crower, Isky and CompCams are all reputable, reliable brands and all make cams suitable for your application. Go to their websites and read what they say about their various grinds. Since you are going with a carb instead of EFI you have many more options in cam selection. You do not need or want a roller cam for your application. They are way more expensive and add very little if any performance in the RPM range you are planning on.

As for the roller rockers, two very big questions first:
1) Does your head have round holes or oblong slots where the pushrods go through it? It makes a huge difference in what you have to do for roller rockers
2) does your head have bolt-down rockers or pressed-in studs? It makes a difference in what you need to do to convert to roller rockers. Whether you convert to rollers or not, if it has pressed in studs, you really want to tap it for screwed in studs

Also, be aware that roller rockers will probably not fit under a stock valve cover. You will need to either cut and braze 2 stock valve covers to build a taller one or to buy a taller aftermarket cover like a Clifford or an Edelbrock (which are no longer being made and extremely hard to find)


I dont have my head with me right now, it is being port and polished. But i have some pictures which i have cropped in detail so you can see them and maybe guess if it has round holes or oblong slots. What s the difference between them ?? Question 2 I will have to call the p&p shop to ask them. It is a stock 1981 head, it s the stock motor of my 1981 with 70000miles on it :). Thank you for advising my of the valve cover i was going to sand it and paint it but now i may go for a Clifford one.. Here are the pictures:
http://i1121.photobucket.com/albums/l502/freeskee/Bronco/tapa2_zpsae1ca784.jpg
http://i1121.photobucket.com/albums/l502/freeskee/Bronco/tapa1_zps3bd98dd8.jpg
I didnt use the image code because images are too big, sorry. Thank you

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StrangeRanger
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Re: Rebuilding my 300, some doubts

Post #7 by StrangeRanger » Fri Apr 05, 2013 2:00 pm

You have pressed-in studs and oblong slots for the push rods.
You should have the machine shop pull the studs and tap the holes for screw in studs. They may have done this already, it's a pretty normal part of prepping an head for a performance engine. Tell them not to get too enthusiastic on the port work, a cleanup is all that is required, they need to spend their efforts on pocket-porting the valve bowls. That is where the big gains are to be had.

Since you have the pushrod guide slots, roller rockers are a simple bolt on, no guide plates are required just a pair of jam nuts for each stud. roller rockers for the ford 300 have at times been available from Crane, CompCams and Harland Sharp and possibly some others. I don't know if Crane still makes theirs. If they do they are the best choice. If they have discontinued them, the Harland Sharps are probably your best bet.
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

julianc
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Joined: Wed Dec 19, 2012 5:28 pm

Re: Rebuilding my 300, some doubts

Post #8 by julianc » Fri Apr 05, 2013 3:50 pm

StrangeRanger wrote:You have pressed-in studs and oblong slots for the push rods.
You should have the machine shop pull the studs and tap the holes for screw in studs. They may have done this already, it's a pretty normal part of prepping an head for a performance engine. Tell them not to get too enthusiastic on the port work, a cleanup is all that is required, they need to spend their efforts on pocket-porting the valve bowls. That is where the big gains are to be had.

Since you have the pushrod guide slots, roller rockers are a simple bolt on, no guide plates are required just a pair of jam nuts for each stud. roller rockers for the ford 300 have at times been available from Crane, CompCams and Harland Sharp and possibly some others. I don't know if Crane still makes theirs. If they do they are the best choice. If they have discontinued them, the Harland Sharps are probably your best bet.


Okay, so I should tell them to pull the studs and tap holes ?? But how do I know which diameters and lenght of stud to choose ?? 7/16 or 3/8 ?? My common sense says that it should be 3/8 since it involves less machining than 7/16. But maybe 7/16 is more used thread size i don t know. Crane doesn t make them any more, so i ll go for harland sharps. Just to know, what are oblong slots ??
Juli

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StrangeRanger
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Re: Rebuilding my 300, some doubts

Post #9 by StrangeRanger » Fri Apr 05, 2013 4:12 pm

If the Babblefish auto-translator is working properly: "ranura oblonga"

Where the pushrod passes through the head, the older heads have an oblong slot which limits the side-to-side motion of the pushrod and therefore any unwanted rotation of the rocker arm about the stud, other heads, mostly late model ones, have a large round hole which provides no side-to-side guidance. These heads typically use the bolt-down pedestal rockers which are prevented from rotating by a guide that is part of the pedestal assembly.

I had no idea whatsoever what type of head was used by Ford Argentina. That is why I asked.
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

julianc
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Re: Rebuilding my 300, some doubts

Post #10 by julianc » Fri Apr 05, 2013 4:29 pm

StrangeRanger wrote:If the Babblefish auto-translator is working properly: "ranura oblonga"

Where the pushrod passes through the head, the older heads have an oblong slot which limits the side-to-side motion of the pushrod and therefore any unwanted rotation of the rocker arm about the stud, other heads, mostly late model ones, have a large round hole which provides no side-to-side guidance. These heads typically use the bolt-down pedestal rockers which are prevented from rotating by a guide that is part of the pedestal assembly.

I had no idea whatsoever what type of head was used by Ford Argentina. That is why I asked.

Okay i understood :lol: . All the Bronco s here in Argentina are mostly from USA and Canada. And very few from Venezuela which were 4x2. Last one to buy all these stuff: how do i choose rocker arm stud diameters and length ??

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StrangeRanger
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Re: Rebuilding my 300, some doubts

Post #11 by StrangeRanger » Fri Apr 05, 2013 7:20 pm

The length and thread on the part of the stud that sticks out should match the stock stud.
Your machine shop can tell you the length, thread diameter and pitch for the part that screws into the head.
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

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