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Discussion Starter #1
Hi

Just joined after having a look around and this seems to be the place to ask so here goes.

Bought an F100 a while ago and was told it was a 351, Only problem is the motor was smokey as hell so swapped it for another which has had a big end knock from the word go but anyway.....

Pulled the original motor apart and find it is only a 302 not the 351 that I was told it had. Not happy but is done.

What i need to know is how to make it a 351 as am recoing the motor to go back in the truck. Do I simply drop a 351 crank in and use the same rods etc or are the rods different between the two.
Am new to all this as have never done any work on a Clevo before, Has all been Jap stuff until now.


Hope it all makes sense and thanks in advance for any help/info.
 

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STROKE ME
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351 is completly different. They are alot wider than a 302. To make it a 351,you'll have to buy a 351. You could stroke the 302, and make it a 347,or 331. You will have 351 power that way,if thats what your after.
 

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Hi m.j.h,
91GT347 has made the assumption you have a Windsor, not a Cleveland. Since you have posted in the Cleveland forum i guess you know you have a Cleveland, not a Windsor.

If you are unsure, look at the front of the motor and if the timing cover housing is cast on to the block upi have a Cleveland. If you are still unsure post a pic and we'll tell you.

As for engines, the 302C and 351C have the same block. A change of crank,rods and pistons will increase your engine size to 351.

Depending on your budget, you could find these parts cheaply at the motor wreckers, or if you have a bit more cash, you could go for a stroker and get anything up to 408 cubes out of your Cleveland block. There are plenty of stroker kits around these days at good prices.

Given you have a heavy truck, a stroker may be worth thinking about. There are lots of guys on here that have done strokers and can help you get it right for your truck.

Hope this helps
gus351
 

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Hotrod Drag & Street Car
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also make sure you use the correct heads. 302 heads on the 351 will give very high compression aprox 11:1 with stock aussie pistons. 10:2 with u.s. dish tops. if you dont want this comp ratio then get some 351 heads. 302 heads have a sort of kidney shaped combustion chamber, 351 heads have a round combustion chamber, both heads are a bolt on job(no mods needed) you can get a piston that will allow you to run the longer 302 clevo rods with a 351 stroke, a bit more costly but great for torque, smooth revs and LPG. cheers
 

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Discussion Starter #6
cjperformance said:
also make sure you use the correct heads. 302 heads on the 351 will give very high compression aprox 11:1 with stock aussie pistons. 10:2 with u.s. dish tops. if you dont want this comp ratio then get some 351 heads. 302 heads have a sort of kidney shaped combustion chamber, 351 heads have a round combustion chamber, both heads are a bolt on job(no mods needed) you can get a piston that will allow you to run the longer 302 clevo rods with a 351 stroke, a bit more costly but great for torque, smooth revs and LPG. cheers
Exactly what I want the motor for.
Sounds like I will go with a new crank, 302 rods I have and some new dished pistons to suit.

Thanks for the replies and to answer another posters question, Yes it is definatly a Cleveland block I have not a Windsor. I know this cause the water outlet is in the block not the manifold. Only way I know to tell them apart.LOL
 

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STROKE ME
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Yeah I just noticed the "never done any work on a Clevo before" in the last paragraph. Didnt notice which forum I was in either. Damn,I need to pay more attention huh ? Sorry about that. lol

Thanks alot for the compliment cjperformance. Its getting there.
 

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Hotrod Drag & Street Car
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m.j.h. the dish pistons wont work if using 302 length rods as the pin height will be different. the dish tops are a replacement for the 73 u.s. unleaded 351 and you need to use 351 rods with these. but they do give a great comp ratio with 302 heads. that is your cheapest way to achieve that 10.2:1. if you use the 302 rods and the appropriate pistons (or 351 rods and flat top standard type pistons) with 302 heads , you will be up to around 11.0:1 to get this down to 10.2:1 you will need to do some calculations and modify the combustion chamber accordingly. more work but worth it. any questions just ask me or if you prefer i can build the motor for you, either in parts, partially assembled or fully assembled ready to bolt in and start. cheers.
 

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Ford Nutter
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Hey there Im building a 351 using a D2AE block and 302 closed chamber heads. Tell me wats the difference between a 4MAB crank and a normal 351 crank?? Ive got a good 4MAB crank(needs a polish). I measured the bore taper using the good old ring and feeler gauge method and have on average 0.006" on a virgin bore..Will I need to get my block bored? Any suggestions?? Cant afford a stroker just want a nice strong tyre smoker..
 

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Hotrod Drag & Street Car
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hi kiwi. i would recomend that you rebore the block if you have 6thou taper. the 4MAB crank has a higher nodular (grey) iron content which basically makes it a bit stronger than the 4MA or the Aussie 351 crank. the 4MAB was mainly used in 351 4V, 4V High Output (different to our GTHO engine), Cobra Jet and Boss engines (Boss is "basically" the same as the GTHO phase 3 engine), The 4MAB crank used in 71 Boss 351 was selected for hardness (a 902 nodularity rating was required) the hardness testing stamp is found on the front crank counterweight on these cranks. Same said, all clevo cranks are good and will give you no worries under performance use. Any questions just ask. cheers.
 

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Hotrod Drag & Street Car
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just a thought on using 302 heads on your 351. if you stay with the stock type flat top pistons you will have around about 11:1 compression ratio. so unless you run only LPG or raceing fuel it may be a bit high for street use.
if you use the 72 351 low comp piston that has about a 12cc dish and also use the 302 heads you will end up with about 10.2:1 comp ratio. perfect for hi octane petrol or lpg. a great cam in such a set up for mild auto use would be Crow # 21665 or for manual or about 2800 convertor try crow# 211367 (both hydraulic cams) or if you want solid lifters try crow # 21773. these will give you a very grunty street engine that will respond well within the usual ranges of street use and be decent on the track also. cheers.
 

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Ford Nutter
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Thanks that helps heaps, I will definately be going with the dished pistons. Im a bit suspect about the quality of the fuel we get over here and believe the 96 octane petrol is probably a bit less than that. In saying that I dont want to be pulling up at the airport for av gas so will just go for 98 BP ultimate with a bottle of octane booster for good measure. I will be running an auto because my mrs will be driving it too.. Cheers for your advice......
 

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Hotrod Drag & Street Car
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no ploblem kiwi. if you go for the first cam i recommended it will be grunty but still very drivable even if you use a stock torque convertor, but i would suggest a 2200 convertor for the best basic performance. performer intake, 600-750vac sec carb, extractors and dual 2.25" or 2.5" exhaust with balance pipe and lukey or similar straight thru type glass pack mufflers and with the mild cam you will make very strong and ultra user friendly tyre smokin power. The other cams will need around 2600 min stall, weiand xcellerator or edelbrock torker type intake to give the best, 750vac carb, 4 into 1 extractors and dual 2.5" exhaust as previously described. it will still be very drivable but a bit more savage from over 3000rpm. and will really sound the part too! just depends how game the mrs is , or how game you are when she's driving! cheers.
 

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Kiwiclevo. Our gas is just fine to run with 302C heads on the 351C rotating assembly, just so long as the cam has a duration of 225 @ 050 or greater. You hardly even need to back the timing out, maybe maximum of 32-34 BTDC, but keeping initial around 12 BTDC. We used to run this combo before they even brought in Ultimate, so we only had 96RON gas. Call me if you need any info, I'm just over the Kaimai's in Hamilton. 0274 380 739.

Cheers
xafalcon
 

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HI there i'm currently building a 351 clevo its got a 351 crank with 302 rods and low skirt flat top pistons with a 0 deck height
what i was wondering was if there is a jig or guide plate i could buy so that i came put the valve reliefs in the side of the bore as i will be running 2v open chamber heads with 4v valves
Thanks a bunch :)
 

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Hotrod Drag & Street Car
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hi, for 4V block valve relief's i usually use a head gasket that i have marked from a factory block as a template. but when you want a spot on job specific to the heads you'll be using, do as follows, with block bare, put valves into heads using only a piece of insulation tape to hold valves in(wrapped around valve stem) sit heads on bare block using an old, or correct thickness head gasket, then with engine upside down on a stand, one by one open each valve untill it touches the edge of the block and mark your valve releif from inside the bore with a marker pen. turn engine up right way, remove heads, measure how far up the bore the highest point of piston ring travel will be, then grind in your valve relief notches staying at least .040" above maximum ring travel. also, while your at it, gasket match the oil drain back passages in the block and heads(front and rear) you will be amazed at how far out of alignment most of these are. also match the oilpump output hole to the engine block. hope that helps. cheers
 

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howdy i got 2v open chamber head that have been ported and a comp cams camshaft specs: 248' @.050" and .605" lift
i was told a cam like this wouldn't like constant revs like highway drive is this true? and will i need a vacuum tank? thanks
 
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