78' 351M Engine Question
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Junior User
Joined: Oct 2000
Posts: 51
Likes: 0
78' 351M Engine Question
Hi Everyone!
Need some advice and have a couple of questions. The time has come to rebuild my 351M. I plan to have it rebuilt as a 400. No money for a 460 swap at this time or in the near future.
I'm going to have a local shop rebuild it and had a couple questions.
1) I'm gonna pull the motor and the shop is asking about $900 for the rebuild and $75 dollars for the 400 crank. Does this sound reasonable to you guys?
2) I had previously planned to build the engine with more performance so I bought some parts on ebay for the engine. Now I'm having second thoughts and will probably go with a stock rebuild.
I had questions about the parts i bought:
a) I purchased a Weiand Stealth single plane competition manifold. My friend tells me i messed up and shoulda bought a dual plane, probablt an edelbrock. Can you guys tell me about the differences between a single and dual? Also, I'm more interested in torque, so will the manifold I got not be the right manifold for me?
b) I bought Hooker headers with 3" collectors. The owner had them ceramic coated but changed engines, so they are like new. Again, I now learned that with such big collectors this would probably be better for a street truck to make lots of HP. True yes?
I jsut wanted to know your thoughts and experiences with such parts.
Thanks and I appreciate all the help!
Steve
Need some advice and have a couple of questions. The time has come to rebuild my 351M. I plan to have it rebuilt as a 400. No money for a 460 swap at this time or in the near future.
I'm going to have a local shop rebuild it and had a couple questions.
1) I'm gonna pull the motor and the shop is asking about $900 for the rebuild and $75 dollars for the 400 crank. Does this sound reasonable to you guys?
2) I had previously planned to build the engine with more performance so I bought some parts on ebay for the engine. Now I'm having second thoughts and will probably go with a stock rebuild.
I had questions about the parts i bought:
a) I purchased a Weiand Stealth single plane competition manifold. My friend tells me i messed up and shoulda bought a dual plane, probablt an edelbrock. Can you guys tell me about the differences between a single and dual? Also, I'm more interested in torque, so will the manifold I got not be the right manifold for me?
b) I bought Hooker headers with 3" collectors. The owner had them ceramic coated but changed engines, so they are like new. Again, I now learned that with such big collectors this would probably be better for a street truck to make lots of HP. True yes?
I jsut wanted to know your thoughts and experiences with such parts.
Thanks and I appreciate all the help!
Steve
Tuned
Joined: Feb 2000
Posts: 309
Likes: 0
From: michigan
78' 351M Engine Question
hi, oh yes the weiand stealth intake is way ,way to much intake for a stock rebuild this intake if i remember right best performs above 3,500 r.p.m. these are for high h.p. & high r.p.m. a dual plane is the best for your engine, plus you will get much better performance and gas mileage with this intake.
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
78' 351M Engine Question
I would definitely ave to agree with cobrajet. If you are looking for any amount of low end torque you have the wrong intake. As for the headers I would use them because it will sound good and give you more power. Just use a muffler that will give you some good backpressure. Definitely go with the 400 crank.
Elder User
Joined: Jun 1999
Posts: 861
Likes: 0
From: SE PA
78' 351M Engine Question
Just another agreement with the intake, too much for torque. The headers, almost all come with a 3" collector, got to remember, the 400 is a large engine and will need to breath on that side even for torque. Do keep the exhaust size in the 2 1/4" to 2 1/2" range unless going with a single, then maybe even a 3", again with decent mufflers, no straight pipes. Try to get a crossover worked into the dual system, this will boost low end somewhat also. Price on the crank sounds reasonable. Might consider an upgraded cam, again, nothing to wild, an RV type with a dual pattern (more lift and duration on the exhaust side), they respond well to these and shouldn't bump the cost very much but will make a big difference in output when combined with the headers. To keep costs down, might consider anything you can assemble yourself, like installing the heads, water pump, oil pump, pick-up and pan, intake ect., ect. if you haven't already figured on doing such things yourself!
Posting Guru
Joined: Aug 2000
Posts: 2,416
Likes: 4
From: PacNW
78' 351M Engine Question
Rebuild price sounds pretty good. $75 for a redone crank is a very good price. As long as you're buying new pistons anyway get the flat top Ohio PnP #1282 and have them put in. You simply can't go wrong with a little more compression on these motors.
Put the intake manifold back on eBay and get yourself a dual plane Edelbrock or Weiand.
Don't worry about the collector size. Hell if you can afford it you could use a 3 inch all the way back. Any full length exhaust system is going to provide enough back pressure. You can get away with a 2.5" dual system without any problem.
Put the intake manifold back on eBay and get yourself a dual plane Edelbrock or Weiand.
Don't worry about the collector size. Hell if you can afford it you could use a 3 inch all the way back. Any full length exhaust system is going to provide enough back pressure. You can get away with a 2.5" dual system without any problem.
