Low budget 5.9 magnum build

[Jonnylightening]

I'll give you alittle run down of what I'm doing. Roughly 10 years ago I built an 87 D150 to sled pull, yes 2wd. A few years later I swapped in a 4x4 chassis and pulled in the SB street class with a mild 400. At that time the C.I. rules (412ci) allowed me to use my BB. Since then the class got outta hand with guys running 600-700HP Small blocks and they outlawed the use of a BB. I still have the truck but it saddens me because it's just collecting dust and most of the engine parts got used on my brother's Cordoba. With that being said I opted to jump down to the SB showroom class. I have a magnum block, SCAT 9000 cast crank (3.58), SCAT forged I beam rods, and a set of used forged flattop pistons with valve reliefs(don't know the make). I want to be able to drive the truck to and from the pulls. Rules for that class allow 3 bolt ons (headers, Holley carb, and intake) they consider a lopey idle an add on. I figure if I go with a bigger cam, intake, and headers that would give me my 3 add ons. I have a Carter AFB but being they were a Mopar carb before edelbrock they can't ***** about that. I'm trying to get as close to 400-450HP at the lowest possible cost. I'm not afraid to get out the die grinder to help my goals. I'm all about "Made in USA" but cheap is not always made in USA. With that in mind Im looking for opinions on intakes and heads for the magnum. I was looking at the Promaxx replacements and others. Also was checking out the Chinese Air gap. Any opinions are appreciated!

 

[rumblefish360]

3 bolt in’s?

Holley
RPM
1-3/4 or larger header.
Cam? No lopey idle? No problem! Solved in to ways!
Wide LSA and/or Rhodes lifters

Say no to the chink knock off intakes.

 

[Slantsix64]

i just bought that cheap crosswinds intake everyone complains about , honestly it works great only one of the ports was a hair off but no real problems i love it. I got a 5.2 magnum stock camshaft for sale 251/260 duration .432 lift its actually better than the stock 5.9 that wouldnt be a add cause it is stock right lol?

 

[Jonnylightening]

3 bolt in’s?

Holley
RPM
1-3/4 or larger header.
Cam? No mopey idle? No problem! Solved in to ways!
Wide LSA and/or Rhodes lifters

Say no to the chink knock off intakes.

Only thing I'm worried about is losing torque with the wider lsa. I'll need the torque to get the sled moving then the HP to keep it going

 

[rumblefish360]

This is a legitimate concern. I get it. To make up for the lack of torque, the cam manufacturers back in the day (Crane) would suggest upping the compression ratio which was normally high, to offset the torque loss.

Your forged pistons sit where in the block? Zero deck?
Combined with a thin head gasket and small cc chamber of the Magnum head, your ratio should go up pretty good.

The wife’s 360 @030 over combined with zero deck slugs w/5cc reliefs, a Cometic gasket @ a 4.04 X .028 & the TF head that has 60cc chambers runs on 93 best. 89 has gotten by with a little run on after shutting off from time to time. Cam is a Hyd roller at 226 intake on a 110. The ratio comes in over 11-1.

This should help you a bit.

The one thing I noticed (often) is that the wider LSA holds onto peak power longer. This is not in stone but often can be the case. Tighter LSA cams peak early and fall off quicker. That is also not in stone.

Take some time to use the calculators to help predict your tire size and gear ratio for trap speed. This way you can start to pre-sort out the combo.

 

[Jonnylightening]

This is a legitimate concern. I get it. To make up for the lack of torque, the cam manufacturers back in the day (Crane) would suggest upping the compression ratio which was normally high, to offset the torque loss.

Your forged pistons sit where in the block? Zero deck?
Combined with a thin head gasket and small cc chamber of the Magnum head, your ratio should go up pretty good.

The wife’s 360 @030 over combined with zero deck slugs w/5cc reliefs, a Cometic gasket @ a 4.04 X .028 & the TF head that has 60cc chambers runs on 93 best. 89 has gotten by with a little run on after shutting off from time to time. Cam is a Hyd roller at 226 intake on a 110. The ratio comes in over 11-1.

This should help you a bit.

The one thing I noticed (often) is that the wider LSA holds onto peak power longer. This is not in stone but often can be the case. Tighter LSA cams peak early and fall off quicker. That is also not in stone.

Take some time to use the calculators to help predict your tire size and gear ratio for trap speed. This way you can start to pre-sort out the combo.

I still need to send the block to the machine shop. I deffinately want to run a roller cam so it's a toss up between the mag block I have or get a roller pre mag block. The plus of the mag are heads. I know they are not budget friendly but was also considering Hughes roller rockers. The Promaxx heads don't seem too bad. Like the EQs I'd deffinately send them out to be checked before I do anything. I'd use factory mag heads but don't want to throw time and money at them for risk of cracking.

 

[rumblefish360]

The worry of a cracked head is so hugely over rated.
You have a better chance of being nuked by Russia spot on, dead center of your head than having a minor or serious problem with cracked Magnum heads.

IDK what company has Magnum heads as an aftermarket head anymore.

 

[Slantsix64]

The worry of a cracked head is so hugely over rated.
You have a better chance of being nuked by Russia spot on, dead center of your head than having a minor or serious problem with cracked Magnum heads.

IDK what company has Magnum heads as an aftermarket head anymore.

yup i just did a magnum head swap on my 89 roller 318, pulled some used heads off slapped them on my block no issues what so ever.