Description
Review this item in the context of the repair, installation access, nearby parts, and the result the completed job is intended to achieve.
This listing is for two (2) exhaust manifolds and two (2) 4″ 7° risers (elbows) for Mercruiser MODEL 330-370, V8 (B.B.), GM 454/502 CID (1981 up to 0M SN#’s) with raw/fresh water cooling systems without spacers. P/N (2) 51240 (GL51240)+(2) 51140 (GL51140); equivalent to the contents in GLM part number 58242 (GL58242.) **NOT FOR DRY JOINT EXHAUST** THE 4″ RISERS FIT 1981-early 2000’s. Note:Ordering this item will require a signature confirmation upon delivery. Please ship to an address where a signature can be obtained from UPS.
Vehicle information
Available fitment details
Listing compatibility notes
- ) **NOT FOR DRY JOINT EXHAUST** THE 4" RISERS FIT 1981-early 2000's.
Fitment data is provided as a buying aid. Verify the listing against your vehicle and existing part before ordering.
Repair scenarios, installation, companion parts, and use outcomes
Buying guidance
Quick decision
Review this manifolds in the context of the repair and the surrounding components.
Repair scenario
- Identify the symptom and confirm that this is the component required by the repair.
- Inspect nearby connectors, fasteners, and mating surfaces before installation.
Installation notes
- Use the listing instructions when present and follow the vehicle service procedure.
- Professional installation may be appropriate when the repair requires special tools or calibration.
Companion parts
- Inspect nearby fasteners, connectors, seals, fluids, and wear items before starting the repair.
- Use the service procedure and the visible package contents to identify any additional parts or tools required.
Before you buy
- Verify the referenced part number: 58242.
- Compare the listing title, photos, package contents, and specifications with the part being replaced.
- Confirm vehicle compatibility and installation requirements before ordering.
Customer feedback
Ratings and written reviews
3.6 / 5
25 source ratings
Source: Amazon. Imported marketplace feedback is shown for product research and is not a review of a purchase made on this website.
Customer –
Fit perfect !!!
Edward Kluska –
Fit as expected very pleased
Gambrelle –
Item was exactly as described. Fit perfectly in our 80s model Chris-Craft. Fast shipping
Verified buyer –
Worked well and very complete kit, thanks!
David arboleda –
One riser seal melted. It came defective. It had to be replaced by quicksilver. I had to hire mechanic again
Dan VanDerWoude –
Absolute garbage installed these on my boat in March 2021 totally rotted out and destroyed my engine by June 2023. Do yourself a favor and buy OEM mercrusier parts not this junk. One star because I couldn’t do 0 stars
chris m. –
These are for one side of the motor just look at the pictures,you have to put different fittings and hoses on to make it work
W_E_Coyote –
These are great quality but they should come with bolts. They require a different length bolt than the factory manifolds, which is a difficult surprise when you are trying to mount them because they weigh a ton.