doing the 351 swap

viridionplague · Oct 25, 2007

so after many hours of searching and talking with an engine builder ive decided to do the swap. im planning on running either 393 or 408 stroker i havent decided yet. anyways this is what ive got so far

-351w roller block
-blower cam - ??
-lower intake mani - trick flow "r" for 351 or gt-40 351 if it can be found
-oil pan - 160
-distributor - 260
-stroker kit with 9.0 compression - around 1700
-drop mounts ???
-swap headers - 300
-pro m 90 mm maf for 42 pound injectors - 700
-fuel rail rails - 250
-comp pro magnum rockers - 300

i plan on using as much of my stock cobra things as possable i want to make sure i havent missed anything, also i am not sure of a few things such as what cam to run for a blower application, and what size roller rockers 1.6?? 1.7?? the other things ive had a problem finding was the drop mounts.

if anyone can offer any advice for parts and such let me know, the end goal is over 600 rwhp and keeping it under the stock hood

however the current goal is just getting it running and doing whatever i need to while the engine is out to avoid redundancy

Kingcater · Oct 26, 2007

even though this has been covered I would like to know also. Im in the first stages of the same swap. Take lots of pix and keep us updated

Subscribing

BlackVert · Oct 26, 2007

what type of forced induction are you going with? for turbo, i'd go with a shorter stroke, which will help with spool up speed

what heads are you going with?

custom cam or off-the-shelf cam?

i'd go with the rocker ratio recommended by the cam grinder

you need to decide if you want to use the loc-wire head gaskets. they can provide a better seal which can help avoid blowing a head gasket. in a forced induction world, this can be good or bad, depending on your perspective

if using the loc-wires, you will need to have the machine shop o-ring either the heads or the block. most people do the heads, but i have heard of a few that do the block

viridionplague · Oct 26, 2007

i was going to go with a kenne bell supercharger, as for heads i was thinking something like AFR 205's, and for a cam im dont know what would be a good cam, theres like a million out there. wasnt planning on a loc wire at least not right now

chuck943 · Oct 26, 2007

The rule of thumb on these heads are usually for up to 392CI use the AFR 205's for higher up to 427CI use the AFR 225's. The 205's would probably flow good enough but the 351 stroker esp. when you get up to the big block cubes will take alot of flow. It should be a monster with the kenne belle.

Also consider using dished pistons you will get a better fuel quench so you can run on pump gas.

S351Saleen77 · Oct 26, 2007

With the longer stroke it raises the compression so yes you should use a dished piston. I'm running an inverted dome. And I would go with the biggest head you can afford.

You will need alot more than 42lb injectors if you want 600rwhp. You will also need the whole supporting items in the fuel system. Pump lines etc.....I wouldn't run the stock fuel lines at that power level. You have to supply fuel for at least 750 to make 600 at the wheels. The supercharger itself like a Kenne Belle probably takes at least 75hp more to run it. A centri supercharger is more efficient. So your really looking at a 800+hp fuel system. This is the one area you can not go overkill on. If you don't have enough fuel things go bad fast at these power levels.

I know you said you wanted to reuse as much as you could but I would also go with another intake and not try to use your Cobra upper.....Oops I forgot with a Kenne Belle that is your upper, you have to get whatever they have thats the biggest for a lower. I had a Kenne Belle on a 302 and at the time the Cobra lower was the biggest Kenne Belle made a upper for. The Cobra lower is not going to match a big head at all like the AFR 225'S. The ports on the Cobra are way smaller. You can only run what Kenne belle makes their upper for.....I don't know if they make anything that will mate up to a big port head??

Just my 2 cents worth............Torque is not a problem with a 408. I would run a Vortech style supercharger over a Kenne Belle. You still have so much torque it's unreal. I'm making 400ft lbs down low then 500 then over 600ft lbs as it revs. If I made over 600 at the bottom I would never be able to hook it up. On a Mustang dyno I made 571ft lbs at 3750rpm before the tires started to spin on the dyno! I could never get a reading because I would just light em up! I would not want more bottom end power than I'm making now.......I want more up top where I can hook it up

chuck943 · Oct 26, 2007

S351Saleen77 said:
Just my 2 cents worth............Torque is not a problem with a 408. I would run a Vortech style supercharger over a Kenne Belle. You still have so much torque it's unreal. I'm making 400ft lbs down low then 500 then over 600ft lbs as it revs. If I made over 600 at the bottom I would never be able to hook it up. On a Mustang dyno I made 571ft lbs at 3750rpm before the tires started to spin on the dyno! I could never get a reading because I would just light em up! I would not want more bottom end power than I'm making now.......I want more up top where I can hook it up

Yes these motors are torque monsters!!!

For your cam just go to the manufactuers website,like Crane has a tech info sheet you can download and put all your info on and they will tell you the best cam for your application,just put as much info on it as you can like head flow numbers,bore/stroke,etc

http://www.cranecams.com/?show=faxForms&type=street

AP1995V6 · Oct 26, 2007

Someone awhile back told me that KB doesn't make a blower that will breathe well with a 408, and that it'd be best to go with a centrifugal supercharger.

vp6799 · Oct 26, 2007

subscribing.....

I am"really" thinking about doing a 351 swap and this thread looks like it will come in handy.

viridionplague · Oct 26, 2007

thanks for the link to crane ill be shooting an e-mail about the cam.

i have been thinking about doing something other that the KB and if these engines are anything like you say its good to know that. as well ive been looking for a bigger kb with some kind of intercooler and just havent found it.

what supercharger would you recomend, ive looked at vortech and i dont realy like how its mounted on the passenger side, mainly because it makes running some kind of front mounted intercooler a PiTa, i would like something mounted where the battery is. as well if thats the case of not running a KB ill run the Full trick flow "R" series upper and lower.

cant wait till i have the time and cash for this, only problem is today it seems my rear end it taking a crap (no pun intended) guess its time to upgrade to the 31 spline full axle assembly ive been looking at with maybe some 3.55's

porchstang · Oct 26, 2007

I have done the swap. Super easy swap. I would get rid of the EFI all together and put a carb on it. Much easier to tune and then if you have to go with a blower then go with a 6-71 and call it a day. But you can build a NA motor to make over 500 hp and build crazy amounts of torque for fairly cheap.

viridionplague · Oct 27, 2007

ive thought about going with a carb but ive never liked carbs much, as well ive heard they suck down alot more gas than the efi setup, as well this is still going to be a daily driver. dunno why i just dont like the sound of a carb

parchisi · Oct 27, 2007

Stay with EFI. I did it and its not too much of pain, just gotta get a good tune from somebody or learn yourself. A Procharger is a good option for a centri supercharger. Plus, with our years, you can run an intercooler no sweat since the head unit is where the battery usually is, and it can just route the air easily in front of the engine.

I'd also recommend going with AFR 225's. I messed up by going with 185's since I originally wanted this to be emissions legal, and only the 185's offered that. As is, its putting down 530 rwhp at 9 lbs of boost, non-intercooled. I imagine I could be doing a lot better with a set of 225's.

fish254 · Oct 28, 2007

does any one got pics of there engine bays and how much more extra parts are requied like motor mounts and accessories does the regular 94-95 centerfuge supercharger kits work ??

viridionplague · Oct 29, 2007

well ive been doing some research i think im going to go with a twin turbo setup instead of centrifugal supercharger, reasons being that i dont like not being at full boost untill redline while turbos can hit full boost around 3k rpm. price on a twin turbo can be very cheap if you know where to look and a little DIY. the reason from twin turboes is 3 fold theres alot less hot piping in the engine bay and the wow factor this should be fun
.. and number 3 is that if the 408 has so much torque the turboes wont boost untill 3000 rpm so for normal driving its easy to keep the rpms low where a supercharger is boosting all the time and robs more power directly from the engine than a turbo would.

408 twin turbo = the win

S351Saleen77 · Oct 29, 2007

viridionplague said:
well ive been doing some research i think im going to go with a twin turbo setup instead of centrifugal supercharger, reasons being that i dont like not being at full boost untill redline while turbos can hit full boost around 3k rpm. price on a twin turbo can be very cheap if you know where to look and a little DIY. the reason from twin turboes is 3 fold theres alot less hot piping in the engine bay and the wow factor this should be fun
.. and number 3 is that if the 408 has so much torque the turboes wont boost untill 3000 rpm so for normal driving its easy to keep the rpms low where a supercharger is boosting all the time and robs more power directly from the engine than a turbo would.

408 twin turbo = the win

Less hot piping from a twin turbo???

A centri supercharger is just a belt driven turbo, it has a bypass valve so its not boosting all the time it's freewheeling under no load until you floor it.

Also like i said mine has so much torque that with a full Griggs suspension that hooks way better than stock...but with handling 18" tires I have a really hard time hooking it up. I wouldn't want much more down low. If I had a drag race suspension and slicks then maybe I could use it. But even full boost at 3k would be too much for my tires!

Sounds like you know what you want though , good luck

viridionplague · Oct 29, 2007

it does turn out to be less hot piping by about 3 or 4 feet, not much but still less, its also easier to change the boost in a turbo setup, (turn of a nob on the fly) so thats another benifit. i did put alot of thought into it and i just like the idea of a twin turbo setup more than a centifugal in my opinion.

you guys here on stangnet also helped me figure out what i want alot as well thanks for all the help. ill keep you guys posted on how things go when i get around to starting the work

porchstang · Oct 30, 2007

Just buil a N/A car and go racing! Forget about tall this power adder crap and use good old N/A power!

viridionplague · Oct 30, 2007

if only good na power wasnt so expensive

doing the 351 swap

viridionplague

New Member

Kingcater

New Member

BlackVert

viridionplague

New Member

chuck943

New Member

S351Saleen77

Member

chuck943

New Member

AP1995V6

Member

vp6799

New Member

viridionplague

New Member

porchstang

New Member

viridionplague

New Member

parchisi

New Member

fish254

viridionplague

New Member

S351Saleen77

Member

viridionplague

New Member

porchstang

New Member

viridionplague

New Member

Similar threads

doing the 351 swap

New Member

New Member

New Member

New Member

Member

New Member

Member

New Member

New Member

New Member

New Member

New Member

New Member

Member

New Member

New Member

New Member

Similar threads

Privacy & Transparency

Privacy & Transparency