302 build up questions
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Postmaster
Joined: Aug 2003
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From: St. Peter
302 build up questions
alright, I have a set of GT-40 mustang cobra heads. They have the stock crane roller rockers. Very nice looking heads. I want to put a block underneath them. I also have the stock mustang cobra cam. its roller lifter. What year blocks have stock roller lifters? Also, i would be using an a9p computer system to control the engine. With 24lb/hr injectors. I want something that will really kick. Now to build up the block starting with the bottom working my way up
Oil pump? high pressure? High volume? whats the pro's/con's to each? The last 302 i did i just put a standard oil pump in. Will a high volume blow out gaskets or screw anything up like that? whats the difference between high flow/high pressure?
Next is the main bearings. Do i need to get a main girdle? i'm thinking the max hp i'm looking for is at least 300 out of this engine. at what HP do i need a main girlde? Also how is the stock crank in these engines? if i'm wanting to run 300 hp will i be fine with the stock one?
Connecting rods/pistions? anything special here? or will the stocker work? What about pistions? hypertectic (SP?), forged? whats best?
Next, this engine will be going into a truck, will the mustang cobra cam be too high end for it? i'll get new roller lifters, but do i need to get a special size pushrod for the roller rockers or will a stock size work fine on them?
I think thats about all of the questions i have for now. Thanks in advance!
Oil pump? high pressure? High volume? whats the pro's/con's to each? The last 302 i did i just put a standard oil pump in. Will a high volume blow out gaskets or screw anything up like that? whats the difference between high flow/high pressure?
Next is the main bearings. Do i need to get a main girdle? i'm thinking the max hp i'm looking for is at least 300 out of this engine. at what HP do i need a main girlde? Also how is the stock crank in these engines? if i'm wanting to run 300 hp will i be fine with the stock one?
Connecting rods/pistions? anything special here? or will the stocker work? What about pistions? hypertectic (SP?), forged? whats best?
Next, this engine will be going into a truck, will the mustang cobra cam be too high end for it? i'll get new roller lifters, but do i need to get a special size pushrod for the roller rockers or will a stock size work fine on them?
I think thats about all of the questions i have for now. Thanks in advance!
FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
I think all the 5.0 mustangs were roller blocks, and the 87-91 are the best of them. In those motors you not only got the roller cam but a forged crank and pistons, good to 400+HP!! Even the non-forged crank should handle 300hp no problem. The rods are a non issue as well.. easily capable of supporting 300hp. The truck 5.0 from 93 on was roller as well.. but even the non-roller equipped blocks can be converted.
There are differing opinions on forged pistons vs hyper. Some say the hypers seal better, but can be fragile and generally not blower friendly. The forged are stronger but the motor should be warmed up before thrashing because the pistons expand faster than the cylinders and may stick in the bores. This is generally a good practice anyway, though.
I don't think the Cobra motor got a special cam but I'm not 100% sure. The stock 5.0 roller cam is good in a truck, though higher numerically gears(3.73-4.10) will certainly help.
I don't think there is any need for an oil pump other than stock, because 300hp is attainable withing the factory rpm range.. or under 5500rpm.
There are differing opinions on forged pistons vs hyper. Some say the hypers seal better, but can be fragile and generally not blower friendly. The forged are stronger but the motor should be warmed up before thrashing because the pistons expand faster than the cylinders and may stick in the bores. This is generally a good practice anyway, though.
I don't think the Cobra motor got a special cam but I'm not 100% sure. The stock 5.0 roller cam is good in a truck, though higher numerically gears(3.73-4.10) will certainly help.
I don't think there is any need for an oil pump other than stock, because 300hp is attainable withing the factory rpm range.. or under 5500rpm.
Elder User
Joined: Mar 2004
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Roller blocks are the HO's used in most Mustangs, T-Birds, and Lincolns from 1985. Trucks got roller blocks in the mid 90's, and Explorer 5.0's had roller blocks.
The Cobra roller rockers are 1.73 ratio, not 1.6 ratio.
The Cobra heads and Cobra cam together will not give you 300 HP. It will be about 265 at the crank. Porting the heads and/or going to a bigger B303 cam (retaining the Cobra rockers) will be required to crack 300 HP. The lift on a B303 cam at the valve is .519 with the Cobra rockers.
Although it's not officially supposed to work, lot's of people have run the E303 with 1.7 rockers without clearance problems (.530 lift). It's close though. However, the E303 cam provides more low end than most other bigger cams for a 5.0. The E303 provides it's peak tourqe at 2500 RPM and peak hP at 5,500 (6000 with high flow heads).
The B303 with 1.73 ratio rockers is essentially the F303. The F303 provides peak tourqe at 2800 rpm, and peak HP at 6000.
If your talking 300 tourqe then the Cobra cam can do that, if it's a 94/95 Cobra cam. The 93 Cobra cam was weak on low end tourqe (about 270 ft-lb's), so it was revised slightly for 94. The 94 Cobra cam is essentially the HO cam, but the rockers give it .484 lift. The HO cam provides 300 ft-lb's at 3200 rpm.
You don't need a gridle or anything on the bottom end unless your putting out 500+ HP. The stock crank is also fine up to 500 HP. The rods are good too.
HO's from 85 through 93 used TWR forged pistons. After 93, they were hyper. If you plan on spraying it going to a blower or something you want forged pistons, but otherwise the lighter, quieter, and tighter fitting hypers are better.
A high volume oil pump doesn't hurt. I use one all the time. It's BS that they blow out your seals.
The Cobra roller rockers are 1.73 ratio, not 1.6 ratio.
The Cobra heads and Cobra cam together will not give you 300 HP. It will be about 265 at the crank. Porting the heads and/or going to a bigger B303 cam (retaining the Cobra rockers) will be required to crack 300 HP. The lift on a B303 cam at the valve is .519 with the Cobra rockers.
Although it's not officially supposed to work, lot's of people have run the E303 with 1.7 rockers without clearance problems (.530 lift). It's close though. However, the E303 cam provides more low end than most other bigger cams for a 5.0. The E303 provides it's peak tourqe at 2500 RPM and peak hP at 5,500 (6000 with high flow heads).
The B303 with 1.73 ratio rockers is essentially the F303. The F303 provides peak tourqe at 2800 rpm, and peak HP at 6000.
If your talking 300 tourqe then the Cobra cam can do that, if it's a 94/95 Cobra cam. The 93 Cobra cam was weak on low end tourqe (about 270 ft-lb's), so it was revised slightly for 94. The 94 Cobra cam is essentially the HO cam, but the rockers give it .484 lift. The HO cam provides 300 ft-lb's at 3200 rpm.
You don't need a gridle or anything on the bottom end unless your putting out 500+ HP. The stock crank is also fine up to 500 HP. The rods are good too.
HO's from 85 through 93 used TWR forged pistons. After 93, they were hyper. If you plan on spraying it going to a blower or something you want forged pistons, but otherwise the lighter, quieter, and tighter fitting hypers are better.
A high volume oil pump doesn't hurt. I use one all the time. It's BS that they blow out your seals.
Posting Guru
Joined: Oct 2003
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From: Quesnel, BC, Canada
read this guys page front to back and over again. http://www.tomak.net/
specifically this one http://www.members.shaw.ca/tomak/page9.html you can find it on the first link under information as "302 engine theory". The guy took his stock HO shortblock to 611rwhp. Ran 12s on a stock longblock with some machining on the stock parts. I found it very insightfull. He was also running E7's
specifically this one http://www.members.shaw.ca/tomak/page9.html you can find it on the first link under information as "302 engine theory". The guy took his stock HO shortblock to 611rwhp. Ran 12s on a stock longblock with some machining on the stock parts. I found it very insightfull. He was also running E7's
Last edited by pud; Aug 28, 2006 at 02:12 PM.
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Postmaster
Joined: Aug 2003
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From: St. Peter
interesting. I cant wait until i can build up another 5.0. I could rip the 85 block out of my F150 but i dont want to pay the 400 bucks for the special lifters and still have to get a small base circle cam and all that. Plus I kinda want to start from scratch. I think it would be fun to do again. I liked doing the first one alot.
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