High reving 302

[All_Ford_Fun]

Any one know what the "safe zone" is for reving a stock block? My 95 recently gave out , got to looking at all of my parts and realized i have just about everything to build a 306 , but most of this stuff is rated at 7000 to 8000 rpm , could a stock rebuilt block handel reving to 7500? :dontknow:

 

[All_Ford_Fun]

http://www.mustangsandmore.com/ubb/SteveWmaxpistonspeed.html

Based off that , a well built "hd" 306 should be safe right? Or would the slightly heavier pistons kill it ?

 

[Win]

I wouldn't be spinning a stock 302 or even a rebuilt one to 7500. It all depends on what parts you have matched with the motor.

 

[Paul]

Sure a stock block can spin 7500 rpms... for a while.


However, nothing even resembling a stock valvetrain will even approach those RPMs.

 

[All_Ford_Fun]

The block would be the only stock part , with a girdel i might add... Outher wise everything down to arps bolts would be aftermarket... dunno , Just got a bunch of parts and no motor in the stang. Some say it will hold , some say it wont...

 

[coupe5ohh]

spend the money u wud spend on another 302 block and all the parts u wud destroy if the hr302 were to blow and by a aftermarket block and do it right...just my .02..i had this talk with my engine performance teacher already lol

 

[All_Ford_Fun]

Typically i would have allready done that , but like I said this is just extra parts from past projects that i have now lol. But i think i just going to sell off some surplus and buy a boss instead

 

[IceMan]

The block will not handle anything over 7000. It may last for a little while, but it will go out on you. N/A combos on stock block shouldn't be more than 6500. With power adder keep it under 6000.

 

[All_Ford_Fun]

Ive got a set up that would be a 331 in the 6500 rpm range and should make 450/475hp at the crank , came accross it last night. I think that's what im going to go with. Only question would be will it be alright with a 100 shot on it? I doubt id spray it more than maybe 5 times a year. Just kinda wanting to make use of the parts I have laying around

 

[IceMan]

You are pushing your luck with that 100 shot, but it may take it. But yet again, it may not. I have NEVER had an aftermarket block and I have had cars well in the 600 RWHP + range, but I was prepared for the fact that the block may not take it, and I was fine with that. IF you are going to build a stock block, be ready for mayhem and the fact that block may not handle 500-550 hp. If you want it to last, keep it about 400-450 hp. My cousin has a stock 95 shortblock with an S-trim and supporting mods, making 424 RWHP running low to mid 11's since 2006. He has put a ton of street miles on it too. He is bracket racing the car again this year.

 

[All_Ford_Fun]

I may just go ahead n build it , its stuff I've acquired over the years and all its going to coast is the price of the trip to the machine shop so wth , why not...

 

[LAFENATU]

Sure a stock block can spin 7500 rpms... for a while.


However, nothing even resembling a stock valvetrain will even approach those RPMs.

Nothing wrong with valve float to be followed by snapped springs etc. ccasion14:

 

[eades5.0]

RPM and det are the main things that take a stock block out

 

[Paul]

I may just go ahead n build it , its stuff I've acquired over the years and all its going to coast is the price of the trip to the machine shop so wth , why not...

Unless the machine shop is going to give you a solid roller camshaft, solid roller lifters, crazy expensive valvesprings, expensive pushrods, and shaft-mount rockers... it's going to cost a lot more than the trip to the machine shop.

Paul.

 

[Paul]

Oh, and just in case you're wondering what happens when you don't spend top dollar on valvetrain parts when trying to spin that RPM... here is Exhibit A:


12:1 Compression Ratio Solid Roller 331 cubic inch road race engine. Solid roller camshaft, lifters, custom 3/8" pushrods, crappy rockers, and a set of insanely expensive valvesprings with almost 800 pounds "open" seat pressure.

The pretty rocker looks a little deformed here:

But wait! Something is amiss... :confused1:

Which caused the valve to drop into the engine at ~73-7400 rpms...

Which ended up doing so much damage that the race block had to be sleeved, the head welded and repaired, and all I got for it was this piston that looks like a chinaman laughing at my sorrow.

Pay now, or pay later.

Paul.

 

[BlkoutGT]

lol at the last pic... So would it be safe(ish) to say keep the rev's below 7k? And of course upgrade the valve train.
Paul, how long did that motor last until it went pop?

 

[All_Ford_Fun]

Yea , I've seen that one b4... I'm going to try to keep it around 63oo , 65oorpm and just hope for the best.
Tho I am going to get better rockers now lol. The rest of my parts are pretty nice , rockers are cheepies that have me gun shy now and while I like chinese food , I'm going to avoid the umm , light weight , high flowin chineese piston you made lol

 

[Paul]

lol at the last pic... So would it be safe(ish) to say keep the rev's below 7k? And of course upgrade the valve train.
Paul, how long did that motor last until it went pop?

Most of the time, there's no need to spin over 7000 rpms unless you're doing something nutty, and it costs a lot of money to rev that high.

I would say it probably saw about 50 hours of track time before it let go. The powerband of that motor was 4500-7700+, but he limiter was set at 7400 to try to make it live.

Paul.

 

[Pure84GTT]

http://www.youtube.com/watch?v=Pbx0OAsZ15Y

a friend built this as a joke of sorts in high school, this car was shifted at 7000 for about a month... then just about everything let go..

fly cut stock 89 5.0 with e cam, ported and milled stock heads, PARKER FUNNEL WEB intake LOL ! generic 650 4bbl carb

believe it or not there was a sweet spot where the car actually made some good power, but it was very short lived lol

it lost to a bolt on 93 gt with a 3:55 gear

it sounded good at least lol