WHAT IS THE BEST 351 BLOCK TO USE?
- Thread starter laford1986
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^^^Correct
Here is some more detail from my swap FAQ
http://www.freewebs.com/vristang/fox351wswapfaq.htm
Background Info-
Here is some more detail from my swap FAQ
http://www.freewebs.com/vristang/fox351wswapfaq.htm
Background Info-
The major disadvantage of the 302 is its lack of strength at high power levels. Most will agree that at ~500hp the factory 302 block will try to split in half. For many the solution to this is an aftermarket 302 block.
Another alternative is to swap in a 351w block. There are 2 production blocks available; the 69-70 blocks had a deck height of 9.480”, and the 71 up blocks had a deck height of 9.503.” This is compared to the 302 deck height of 8.200” The 69-70 blocks also had thicker main webs and higher nickel content, making them significantly stronger. From 70 to 74 the 351w maintained the higher nickel content, but lost some of the material in the main webs. Another small reduction in the main web thickness occurred in 75, along with another reduction in Nickel content (supposedly), but after that the block remained basically unchanged until it ended production. From 1994 on, all 351w blocks were equipped with roller cams/lifters.
Another alternative is to swap in a 351w block. There are 2 production blocks available; the 69-70 blocks had a deck height of 9.480”, and the 71 up blocks had a deck height of 9.503.” This is compared to the 302 deck height of 8.200” The 69-70 blocks also had thicker main webs and higher nickel content, making them significantly stronger. From 70 to 74 the 351w maintained the higher nickel content, but lost some of the material in the main webs. Another small reduction in the main web thickness occurred in 75, along with another reduction in Nickel content (supposedly), but after that the block remained basically unchanged until it ended production. From 1994 on, all 351w blocks were equipped with roller cams/lifters.
fidstang
New Member
Has anyone ever machined a 351 to a deck height of a 302? Yeah, I know what your thinking why! Just a curious question.
fidstang
New Member
That's what I thought. Has anyone ever figured out the real reason why the Mexican 302 blocks are stronger then the north american ones?
NosPony
New Member
352Ford2
New Member
352Ford2 said:
I appreciate you bringing this up.
I would like to fix any errors you or anyone else finds in something I have written.
Can you provide more detail.
How to identify these blocks?
More detailed info on the trucks/broncos?
Were there even any cars that used the 351 in that time frame?
Do you have any links that discuss this?
I appreciate the contribution of knowledge
jason
I would also look into 351 Marine blocks. I have a 74 marine 351 and the machinest said he has never seen that much beef in a production 351. You can still use all the automotive 351 parts. If you can score the whole short block it would easily be good for 450hp with good bolts. I have heard that the older Marine 351's is good for about 750fwhp.... just what i heard
The Mexican blocks do have more nickel and are a stronger casting.
The Mexican blocks do have more nickel and are a stronger casting.
yes i agree. marine engines are always the best of the automotive blocks. 440 marine engines for mopars for intance were 67 hp blocks. one of the strongest blocks in the 440's. i have a 72 windsor block and its right in the middle of the high nickel content blocks you want to look for. it has worked for my car for the past 5 years.
I'm having a 408 built by McAllister Brothers using a 69 block...and it will have a D2 Procharger feeding it. The car will be more cruise and show than all-out drag [although it will get a few runs...before being thrown off the track!] so I didn't go with a Dart block. Tracy believes we will be okay at 750-800hp [flywheel]...just hope the 40 y/o car is!
pb_paulie_b
Founding Member
The 69' block is the strongest stock 351w block. High nickle content and thicker main webbing. It is also flat at the top of the main webbing. This make it possible to go with 4 bolt mains.
View attachment 460124
View attachment 460124
352Ford2
New Member
according to my speed pro book, the only roller 351 w's from the factory are some 1994-1997 light duty trucks (that includes suvs) that have the letter "H" in the VIN number for an engine code. yes suposedidly their are H coded trucks that have flat tappets too.
other than pulling the intake manifold I don't don;t of a way to check, but I am willing to bet engine block casting numbers would tell you (they have to be cast diffrent with bosses and deeper lifter bores.
other than pulling the intake manifold I don't don;t of a way to check, but I am willing to bet engine block casting numbers would tell you (they have to be cast diffrent with bosses and deeper lifter bores.
vristang said:
Thanks for coming back with that follow up info.
Does anyone have a pic of the lifter valley of a factory roller 351w?
I am doubtful that the casting was actually changed. If it was I would think that even the non-roller blocks would have the bosses for the roller gear. It would be more expensive to have 2 different engine blocks in production.
Interesting stuff,
jason
Does anyone have a pic of the lifter valley of a factory roller 351w?
I am doubtful that the casting was actually changed. If it was I would think that even the non-roller blocks would have the bosses for the roller gear. It would be more expensive to have 2 different engine blocks in production.
Interesting stuff,
jason
in all practicality, the later blocks are obviously easier to come by, and that's the block I'd go with. then again, I'd be lucky to get anywhere near 500 horse on my budget.
fyi, all 94+ 5.8 blocks were equipped to have a roller cam, although most blocks still came flat tappet. Grab a 94+ block, and that roller cam will go right in.
fyi, all 94+ 5.8 blocks were equipped to have a roller cam, although most blocks still came flat tappet. Grab a 94+ block, and that roller cam will go right in.
