351w mods CA smog
Thread Starter
|
Cross-Country
Joined: May 2017
Posts: 82
Likes: 4
351w mods CA smog
hey folks,
I have a 93 van with a 351w in front of an e4od.
I converted the van to 4x4 using superduty parts. both axles have 4.10 gears. it is currently on 33's and i dont want to put smaller tires on it if i can avoid it.
the van is a Sportsmobile camper and weighs around 8000 lbs with full tanks and me in it. it will have another 500 lbs going into it. It struggles mightily climbing in the mountains. I have to take steep grades in 2nd gear at around 35-40 mph and the motor sounds like it wants to throw a rod.
I plan to regear it to 4.56 because I need to put lockers in it anyway, but I have a feeling it will still suffer, not sure what to expect.
the 351 is a speed density motor.
here in California these motors have a primary cat with 2 small inlets, one from each header. You have to run this cat to be smog legal here, I already replaced it with a magnaflow, so its difficult to enlarge the exhaust because the little inlets on this cat continue to be a bottleneck.
the exhaust also necks down to 2" after the second cat for some reason.
is it worth doing shorty smog headers and a full 2.5" exhaust if this primary cat remains a restriction?
also is it worth doing GT40 heads without replacing the intake?
it seems like if you cant find a lightning intake the cheapest one for these motors is the edelbrock and its $1000 for upper and lower.
I am trying decide wether to spend money on this thing or not. I originally wanted to cummins swap it but it would be nice to spend like $500-1000 on the motor and put 4.56s in it and take it wherever i want it to go.
what I could do seems like the following:
K&N intake, e-fan conversion, edelbrock intake, GT40 heads, shorty smog headers, 2.5" catback exhaust. and I could probably get away with punching the guts out of the second cat.
i feel fairly confident i can find a smog shop to ignore those mods if it has cats and blows good numbers but hey who knows..
anyone want to speculate what hp/tq i could expect from all that?
Thanks for any help
Mitch
I have a 93 van with a 351w in front of an e4od.
I converted the van to 4x4 using superduty parts. both axles have 4.10 gears. it is currently on 33's and i dont want to put smaller tires on it if i can avoid it.
the van is a Sportsmobile camper and weighs around 8000 lbs with full tanks and me in it. it will have another 500 lbs going into it. It struggles mightily climbing in the mountains. I have to take steep grades in 2nd gear at around 35-40 mph and the motor sounds like it wants to throw a rod.
I plan to regear it to 4.56 because I need to put lockers in it anyway, but I have a feeling it will still suffer, not sure what to expect.
the 351 is a speed density motor.
here in California these motors have a primary cat with 2 small inlets, one from each header. You have to run this cat to be smog legal here, I already replaced it with a magnaflow, so its difficult to enlarge the exhaust because the little inlets on this cat continue to be a bottleneck.
the exhaust also necks down to 2" after the second cat for some reason.
is it worth doing shorty smog headers and a full 2.5" exhaust if this primary cat remains a restriction?
also is it worth doing GT40 heads without replacing the intake?
it seems like if you cant find a lightning intake the cheapest one for these motors is the edelbrock and its $1000 for upper and lower.
I am trying decide wether to spend money on this thing or not. I originally wanted to cummins swap it but it would be nice to spend like $500-1000 on the motor and put 4.56s in it and take it wherever i want it to go.
what I could do seems like the following:
K&N intake, e-fan conversion, edelbrock intake, GT40 heads, shorty smog headers, 2.5" catback exhaust. and I could probably get away with punching the guts out of the second cat.
i feel fairly confident i can find a smog shop to ignore those mods if it has cats and blows good numbers but hey who knows..
anyone want to speculate what hp/tq i could expect from all that?
Thanks for any help
Mitch
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Not enough to justify the cost. It's been done, there was a magazine article(remember those) from back in the day that did a comparison build on a 5.8 powered F250 and a 5.9 Cummins powered Dodge, yeah not exactly apples to apples but it was a diesel mag and the oil burner produced more gains for the money spent(surprise), but it was still instructive none the less. They put edelbrock heads, intake, and shorty headers on an otherwise stock 5.8 and got maybe 20hp, and a turbo on the cummins and got like 100hp
Anyway... I know form personal experience that the stock cam in these motors is the primary bottleneck, and I also know from building my own 5.8 that the Crane 444232 is the cam to have for an SD EFI friendly build. Problem is Crane is long gone so it's not likely you will find a copy to buy but the specs are still all over the internet so it wouldn't be hard or expensive to have a cam grinder cut one for you. And that is pretty much all you need, this cam with nothing but headers and a decent cat back will make 260-275hp and 375 lb/ft torque from a bone stock looking 5.8.
Anyway... I know form personal experience that the stock cam in these motors is the primary bottleneck, and I also know from building my own 5.8 that the Crane 444232 is the cam to have for an SD EFI friendly build. Problem is Crane is long gone so it's not likely you will find a copy to buy but the specs are still all over the internet so it wouldn't be hard or expensive to have a cam grinder cut one for you. And that is pretty much all you need, this cam with nothing but headers and a decent cat back will make 260-275hp and 375 lb/ft torque from a bone stock looking 5.8.
Thread Starter
|
Cross-Country
Joined: May 2017
Posts: 82
Likes: 4
Not enough to justify the cost. It's been done, there was a magazine article(remember those) from back in the day that did a comparison build on a 5.8 powered F250 and a 5.9 Cummins powered Dodge, yeah not exactly apples to apples but it was a diesel mag and the oil burner produced more gains for the money spent(surprise), but it was still instructive none the less. They put edelbrock heads, intake, and shorty headers on an otherwise stock 5.8 and got maybe 20hp, and a turbo on the cummins and got like 100hp
Anyway... I know form personal experience that the stock cam in these motors is the primary bottleneck, and I also know from building my own 5.8 that the Crane 444232 is the cam to have for an SD EFI friendly build. Problem is Crane is long gone so it's not likely you will find a copy to buy but the specs are still all over the internet so it wouldn't be hard or expensive to have a cam grinder cut one for you. And that is pretty much all you need, this cam with nothing but headers and a decent cat back will make 260-275hp and 375 lb/ft torque from a bone stock looking 5.8.
Anyway... I know form personal experience that the stock cam in these motors is the primary bottleneck, and I also know from building my own 5.8 that the Crane 444232 is the cam to have for an SD EFI friendly build. Problem is Crane is long gone so it's not likely you will find a copy to buy but the specs are still all over the internet so it wouldn't be hard or expensive to have a cam grinder cut one for you. And that is pretty much all you need, this cam with nothing but headers and a decent cat back will make 260-275hp and 375 lb/ft torque from a bone stock looking 5.8.
wow.. headers, 2.5 all the way back and a cam for 375 lb ft.. you promise? lol
no tune?
Im getting 10-11 mpg now what will that do to my mileage? does it have a chance of still blowing good numbers with a cam? im not an engine guy
Thanks for the info
Mitch
Thread
Thread Starter
Forum
Replies
Last Post
frenchie93
Performance & General Engine Building
9
Aug 15, 2022 08:42 PM
